Cross metathesis of methyl oleate (MO) with terminal, internal olefins by ruthenium catalysts: factors affecting the efficient MO conversion and the selectivity

Abstract

Cross metathesis (CM) reactions of methyl oleate (MO) with cis-4-octene (OC), cis-stilbene (CS) using RuCl₂(PCy₃)(IMesH₂)(CHPh) [IMesH₂ = 1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene; Cy = cyclohexyl] afforded CM products with high MO conversion and high selectivity under high molar (OC/MO, CS/MO) ratios; CM with cis-1,4-diacetoxy-2-butene also afforded metathesis products with high MO conversion under certain conditions. The efficient CM with allyltrimethylsilane proceeded with high activity, whereas the CM with glycidyl ether, β-pinene, and vanillylidenacetone proceeded with low MO conversion.

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Introduction

Olefin metathesis is an important and useful method for efficient carbon–carbon bond formation applied to the synthesis of various organic compounds and polymeric materials,¹ and transition metal–carbene (alkylidene) complexes play an essential role in this catalysis. In particular, cross metathesis (CM) and ring-closing metathesis (RCM) are important methods for the synthesis of valuable organic compounds.² One recent promising application in olefin metathesis is the utilization of bio renewables; olefin metathesis of unsaturated fatty acids³ in vegetable oils, exemplified as oleate in Jatropha oil,⁴ has been considered a target reaction.^5,6 Reports for self-metathesis (SM) of methyl oleate (MO, major component in the Jatropha oil) and CM of MO with ethylene or α-olefin using ruthenium,^5a–e,g,h molybdenum and tungsten catalysts^5f have been known (Scheme 1).

Scheme 1 Self-metathesis (SM) of methyl oleate (MO), and the cross metathesis (CM) with ethylene.⁵

Reported examples for CM of MO with allyl chloride,^6a methyl acrylate,^6b,c,g acrylonitrile,^6c cis-1,4-diacetoxy-2-butene [(Z)-2-butene-1,4-diol diacetate, cis-2-butene-1,4-diyl diacetate],^6d,f ethyl acrylate,^6e allyl cyanide^6h were also known. Although CM has been considered as efficient tools for synthesis of valuable fine chemicals from MO, however, reports for the CM reactions with a series of terminal, internal olefins under the same conditions including exploring the effect of substituents on olefins (including molar ratios), catalyst, temperature etc. still have not well studied yet. One probable reason might be due to a concern for control of selectivity of the desired products that can be often observed in CM (being proceeded under certain equilibrium).^2d,7 For example, the CM reactions of MO with terminal olefins would afforded 4 types of CM products in addition to SM products, as described below. In this paper, we thus wish to present our explored results for the cross metathesis reactions with a series of internal olefins [1,2-disubstituted (bifunctional) olefins] and terminal olefins containing different substituents using ruthenium catalysts.

Results and discussion

As preliminary experiments for an optimisation of reaction conditions, self-metathesis (SM) reactions of MO using ruthenium catalysts, RuCl₂(CHPh)(PCy₃)₂ [Ru(1)], Cy = cyclohexyl, RuCl₂(PCy₃)(IMesH₂)(CHPh) [Ru(2), IMesH₂ = 1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene], were conducted under various conditions (Table 1).⁶ It turned out and it has been known that the metathesis of MO took place with high catalytic activities to reach high MO conversions (even after 20 minutes, runs 5 and 7), but the apparent selectivity on SM products decreased over time course or rather high catalyst loadings (runs 1–3, 5, 6). This is because that the SM products further reacted with MO or the products (called second metathesis, including isomerisation of olefins probably by decomposed catalysts) to afford MO and the other products. Therefore, no significant differences in the apparent MO conversions (on the basis of GC analysis using internal standards) nor selectivities in the SM products were observed, when the reactions were conducted under rather high Ru(2) loading conditions (runs 2, 3 and 6, 9). The reaction at room temperature (23 °C) under low Ru(2) loading thus showed the high selectivity of the SM products (run 8). Ru(1) showed lower conversion of MO and selectivity of SM products than Ru(2) under the same conditions (runs 2, 4). The result conducted in n-hexane was close to that conducted in CH₂Cl₂ (runs 5, 7).

Table 1 Self-metathesis of methyl oleate (MO) by RuCl₂(PCy₃)₂(CHPh) (1) or RuCl₂(PCy₃)(H₂IMes)(CHPh) (2)^a

Run	Ru cat. (mol%)	Solvent	Temp/°C	Time/h	Conv.^b/%	SM1^c/%		SM2^c/%		Select.^d/%
						trans	cis	trans	cis
a Conditions: methyl oleate (MO) 2.00 mmol, solvent 1.0 mL.b Conversion of MO estimated by GC using internal standard.c GC yield estimated according to the effect of carbon number (ECN) rule (vs. internal standard).d Selectivity of SM1 and SM2 based on the conversion of MO. SM1: octadec-9-ene, SM2: dimethyl octadec-9-enedioate.
1	2 (0.1)	CH2Cl2	50	1	62	23	6	15	4	77
2	2 (0.5)	CH2Cl2	50	1	75	18	5	10	3	48
3	2 (1.0)	CH2Cl2	50	1	77	17	4	8	3	42
4	1 (0.5)	CH2Cl2	50	1	66	7	2	9	3	32
5	2 (0.5)	CH2Cl2	50	0.33	80	25	7	7	3	53
6	2 (0.5)	CH2Cl2	50	24	65	19	4	14	4	64
7	2 (0.5)	n-Hexane	50	0.33	79	25	7	7	3	53
8	2 (0.1)	CH2Cl2	23	1	55	24	6	19	5	98
9	2 (0.5)	CH2Cl2	23	1	76	17	5	11	4	49

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Cross metathesis (CM) of methyl oleate (MO) with various internal olefins [cis-4-octene (CO), cis-stilbene (CS), and cis-1,4-diacetoxy-2-butene (DAB)]

On the basis of results in Table 1, cross metathesis (CM) reactions of MO with cis-4-octene (CO), cis-stilbene (CS), and cis-1,4-diacetoxy-2-butene (DAB), shown in Scheme 2, were conducted in the presence of conventional ruthenium catalysts, Ru(1), Ru(2) and RuCl₂(CH-2-OⁱPr-C₆H₄)(IMesH₂) [Ru(3)] in CH₂Cl₂. The results are summarised in Table 2.

Scheme 2 Cross metathesis (CM) of methyl oleate (MO) with various internal olefins [cis-4-octene (CO), cis-stilbene (CS), and cis-1,4-diacetoxy-2-butene (DAB)].

Table 2 Cross metathesis (CM) of methyl oleate (MO) with various internal olefins [cis-4-octene (CO), cis-stilbene (CS), and cis-1,4-diacetoxy-2-butene (DAB)]^a

Run	Olefin	Ru, cat.^b	Equiv.^c	Time/h	Conv.^d/%	CM1^e/%	CM2^e/%	SM1^e/%		SM2^e/%		Select.(1)^f/%	Select.(2)^g/%
								trans	cis	trans	cis
a Conditions: methyl oleate (MO) 2.00 mmol, CH2Cl2 1.0 mL, Ru 0.010 mmol (0.5 mol%), 50 °C.b RuCl2(CHPh)(PCy3)2 [Ru(1)], Cy = cyclohexyl, RuCl2(PCy3)(IMesH2)(CHPh) [Ru(2), IMesH2 = 1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene], RuCl2(CH-2-O^iPr-C6H4)(IMesH2) [Ru(3)].c Based on MO.d Conversion of MO estimated by GC using internal standard.e GC yield estimated according to the effect of carbon number (ECN) rule.f Selectivity of CM1,2 and SM1,2 based on the conversion of MO.g Selectivity of cross metathesis products (%) = (CM1 + CM2)/(CM1 + CM2 + SM1 + SM2). CM1: tridec-4-ene (from CO), dec-1-en-1-ylbenzene (from CS), undec-2-en-1-yl acetate (from DAB). CM2: methyl tridec-9-enoate (from CO), methyl 10-phenyldec-9-enoate (from CS), methyl 11-acetoxyundec-9-enoate (from DAB). SM1: octadec-9-ene. SM2: dimethyl octadec-9-enedioate.h Reaction without solvent (CH2Cl2).
10	CO	1	1.0	17	17	2	2	0	0	1	0.0	18	80
11	CO	2	1.0	1	81	43	41	9	2	8	2	78	80
12	CO	3	1.0	1	82	32	31	8	1	7	1	61	79
13	CO	2	5.0	1	93	88	86	3	0	3	0	>99	97
14	CO	2	10	1	94	93	90	1	0	1	0	>99	99
15	CO^h	2	10	1	80	44	50	2	0	2	0	64	96
16	CS	2	1.0	1	92	45	34	8	2	9	3	67	78
17	CS	2	5.0	1	97	88	76	2	0	3	1	91	96
18	DAB	2	1.0	1	87	65	59	6	1	5	1	86	91
19	DAB	2	5.0	1	80	27	24	4	1	1	1	41	88
20	DAB	2	10	1	67	6	6	1	0	0	0	10	92
11	CO	2	1.0	1	81	43	41	9	2	8	2	78	80
21	CO	2	1.0	8	82	43	40	10	2	8	1	76	80
18	DAB	2	1.0	1	87	65	59	6	1	5	1	86	91
22	DAB	2	1.0	3	90	54	47	7	1	5	1	72	88

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It turned out that reactions of MO with 1 equiv. of CO by Ru(2), Ru(3) took place with high MO conversions even after 1 h, affording both cross metathesis (CM) and self-metathesis (SM) products (runs 11, 12), but the reaction with Ru(1) showed low MO conversion and the selectivities (run 10). It also turned out that selectivity of CM and SM products on the basis of conversion of MO [defined as select.(1), Table 2] by Ru(3) was lower than that by Ru(2), probably due to further reactions (second metathesis etc.) with the products. The MO conversion, and selectivity of CM and SM products increased under high CO/MO molar ratios (runs 11, 13, 14); selectivities of CM and SM (initial metathesis) products reached to almost exclusive (>99%). Moreover, selectivity of CM products [defined as select.(2), percentage of CM products on the basis of CM and SM (initial metathesis) products, Table 2] increased upon increasing the CO/MO ratios. However, the selectivities of both CM and SM products decreased when the reaction was continued for 8 h (run 21), probably due to further reactions (second metathesis etc.) with the products. Similar trend was observed in the CM reaction with CS; conversion of MO, selectivity of CM and SM products on the basis of MO conversion [select.(1)], selectivity of CM products on the basis of total CM and SM products [select.(2)] increased upon increasing the CS/MO molar ratios (runs 16, 17). CM with CO without solvent proceeded with high selectivity of CM product [select.(2), run 15], although selectivity of CM and SM products on the basis of MO conversion [select.(1)] decreased probably due to further reaction, as described above.

In contrast, conversion of MO, selectivity of CM and SM (initial metathesis) products on the basis of MO conversion [select.(1)] decreased upon increasing the DAB/MO molar ratios, whereas selectivity in the reaction with 1 equiv. of DAB (run 18) was higher than those with CO (run 11), CS (run 16) and the MO conversion was also higher than that with CO. This would be probably due to formation of the other carbene species by reaction of DAB (decrease in reactivity by coordination of oxygen atom).^2d It thus seems clear that the conversion of MO and selectivity of the CM products were highly affected by molar ratio and nature of substituent in the internal olefins (which should affect nature of ruthenium–carbene species formed);^2d,7a–e certain optimisation of reaction time (termination at rather initial stage, 1 h) should thus also be required for the purpose.

Cross metathesis (CM) of methyl oleate (MO) with allyltrimethylsilane (ATMS), allyl glycidyl ether (AGE), β-pinene (PN), or vanillylidenacetone (VA)

Cross metathesis (CM) reactions with terminal olefins such as allyltrimethylsilane (ATMS), allyl glycidyl ether (AGE), β-pinene (PN), and with an internal olefin like vanillylidenacetone (VA) were conducted in the presence of Ru(2) under similar conditions (Scheme 3), and the results are summarised in Table 3. As shown in Scheme 3, reactions with terminal olefins (ATMS, AGE, PN) afforded 4 types of cross metathesis (CM) products (expressed as CM1, CM2, CM3, and CM4) in addition to self-metathesis (SM) products.

Scheme 3 Cross metathesis (CM) of methyl oleate (MO) with allyltrimethylsilane (ATMS), allyl glycidyl ether (AGE), β-pinene (PN), or vanillylidenacetone (VA).

Table 3 Cross metathesis (CM) of methyl oleate (MO) with allyltrimethylsilane (ATMS), allyl glycidyl ether (AGE), β-pinene (PN), or vanillylidenacetone (VA)

Run^a	Olefin	Equiv.^b	Conv.^c/%	CM1^d/%	CM2^d/%	CM3^d/%	CM4^d/%	SM1^d/%		SM2^d/%		Select.(1)^e/%	Select.(2)^f/%
								trans	cis	trans	cis
a Conditions: methyl oleate 2.00 mmol, CH2Cl2 1.0 mL, catalyst (2) 0.010 mmol, temperature 50 °C, time 1 h.b Based on MO.c Conversion of MO estimated by GC using internal standard.d GC yield estimated according to the effect of carbon number (ECN) rule.e Selectivity of CM1-4 and SM1,2 based on the conversion of MO.f Selectivity of cross metathesis products (%) = (CM1 + CM2 + CM3 + CM4)/(CM1 + CM2 + CM3 + CM4 + SM1 + SM2). CM1: dec-1-ene (from ATMS, AGE, PN), dodec-3-en-2-one (from VA), CM2: methyl dec-9-enoate (from ATMS, AGE, PN), methyl 11-oxododec-9-enoate (from VA), CM3: trimethyl(undec-2-en-1-yl)silane (from ATMS), 2-((undec-2-en-1-yloxy)methyl)oxirane (from AGE), 7,7-dimethyl-3-nonylidenebicyclo[4.1.0]heptane (from PN), 4-(dec-1-en-1-yl)-2-methoxyphenol (from VA), CM4: methyl 11-(trimethylsilyl)undec-9-enoate (from ATMS), methyl 11-(oxiran-2-ylmethoxy)undec-9-enoate (from AGE), methyl 9-(7,7-dimethylbicyclo[4.1.0]heptan-3-ylidene)nonanoate (from PN), methyl 10-(4-hydroxy-3-methoxyphenyl)dec-9-enoate (from VA), SM1: octadec-9-ene, SM2: dimethyl octadec-9-enedioate.g Reaction without solvent (CH2Cl2).
23	ATMS	1.0	80	10	10	28	26	9	2	8	2	73	78
24	ATMS	5.0	94	36	9	50	49	2	1	3	1	>99	96
25	ATMS	10	96	46	47	48	45	1	0	1	0	>99	>99
26	ATMS^g	10	96	27	37	30	34	1	1	2	0	71	97
27	AGE	1.0	38	1	1	1	1	1	1	1	1	16	50
28	AGE	5.0	55	1	1	1	1	0	0	0	0	4	>99
29	AGE	10	46	1	1	1	1	0	0	0	0	4	>99
30	PN	1.0	77	1	2	0	1	19	3	14	4	55	9
31	PN	5.0	80	5	2	0	1	17	4	13	4	53	17
32	VA	1.0	67	4	4	3	2	17	3	15	4	68	25
33	VA	5.0	74	17	16	13	10	13	3	11	4	80	64

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It turned out that the conversion of MO and selectivity of CM and SM (initial metathesis) products increased upon increasing the ATMS/MO molar ratios (runs 23–25), as observed in the CM reactions with cis-4-octene (OC); selectivities of CM and SM (initial metathesis) products reached to almost exclusive (>99%). Moreover, selectivity of CM products [defined as select.(2)] increased under high ATMS/MO molar ratios; ratios of CM1 : CM2 and CM3 : CM4 (runs 23, 24) or ratio of CM1 : CM4 and CM2 : CM3 (run 25) were also close, suggesting that further CM reactions would be minimised under these conditions.

Moreover, CM with ATMS without solvent proceeded with high selectivity of CM product [defined as select.(2), run 26].

In contrast, the CM reactions with AGE showed rather low MO conversions and low selectivities of CM and SM (initial metathesis) products [defined as select.(1)], although selectivity among the SM and CM products [before further reactions, select.(2)] became high upon increasing the AGE/MO molar ratios (runs 27–29) under low selectivities of the initial metathesis products. This would be probably assumed as formation of certain carbene species (decrease in the reactivity by coordination of oxygen atom, called dormant species) in the reaction with AGE.

Moreover, the selectivities of CM products were low in the reaction with PN probably due to a steric bulk (runs 30, 31).^7c,e The MO conversion and the selectivity of the initial metathesis product on the basis of MO conversion [select.(1)] increased upon increasing the VA/MO molar rations in the reaction with VA (runs 32, 32). The selectivity of CM products [select.(2)] also increased upon increasing the VA/MO molar ratios, but these values were much lower than those in the CM reactions with ATMS. These results also suggest that the conversion of MO and selectivity of the CM products were highly affected by molar ratio and nature of substituent in the olefins (steric bulk, formation of dormant species by coordination of oxygen etc.) employed,^7a–e as demonstrated concerning effect of olefin substituents in CM using ruthenium catalysts.^7e

Conclusions

We have shown that olefin metathesis reactions of methyl oleate (MO), in particular, the cross metathesis (CM) reactions with cis-4-octene (OC), cis-stilbene (CS), and with allyltrimethylsilane (ATMS) conducted under rather high molar (OC/MO, ATMS/MO etc.) ratios, proceeded with high catalytic activities. The CM products with high MO conversions and selectivity of CM reactions could be achieved especially in the reactions with CO and ATMS under these conditions. It also turned out that the conversion of MO and selectivity of the CM products were highly affected by molar ratio and nature of substituent in the olefins employed. Moreover, further reactions (metathesis, isomerisation, additions etc.) including side reactions caused by subsequent catalyst decompositions should be considered for achievement of high selectivities; these are also affected by the type of ruthenium catalysts employed. Therefore, we believe that a series of reactions demonstrated here should be important for better understanding of parameters in this catalytic reactions, although effect of substituents toward the selectivity in the CM reactions were partly known.^2d,7,8 We also believe that the results here should provide useful information for more efficient conversion of plant oil (Jatropha etc.)⁴ or designing the efficient route for fine chemical synthesis using olefin metathesis.

Experimental section

General procedure

All experiments were carried out under a nitrogen atmosphere in a Vacuum Atmospheres drybox unless otherwise specified. All chemicals used were of reagent grade and were purified by the standard purification procedures. Anhydrous grade dichloromethane (DCM) and n-hexane (Kanto Chemical Co., Inc.) were transferred into a bottle containing molecular sieves (mixture of 3A 1/16, 4A 1/8 and 13X 1/16) in the drybox. Methyl oleate (≥99%), cis-stilbene, β-pinene, cis-4-octene, cis-1,4-diacetoxy-2-butene, vanillideneacetone, allyl trimethylsilane and allyl glycidyl ether were used in the drybox as received (Aldrich Chemical Co. or Tokyo Chemical Industry Co., Ltd.) without purification. Grubbs catalyst 1st generation RuCl₂(PCy₃)₂(CHPh) (1), 2nd generation RuCl₂(PCy₃)(H₂IMes)(CHPh) (2) and Hoveyda–Grubbs catalyst 2nd generation RuCl₂(IMesH₂)(CH-2-OⁱPr-C₆H₄) (3) were used in the drybox as received [Cy = cyclohexyl, IMesH₂ = 1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene] (Aldrich Chemical Co.). Nonane and dodecane purchased from Tokyo Chemical Industry Co., Ltd were used as the internal standard (IS) for GC analyses.

The gas chromatograph mass spectrometer (GC/MS) analyses were performed on Shimadzu GC-17A gas chromatograph directly coupled to the mass spectrometer system (MS) of Shimadzu GCMS QP5050. Agilent column model DB-1 30 m length, 0.25 mm in diameter and film thickness and polyethylene glycol stationary phase was used throughout the experiment. Helium was used as the carrier gas at a flow rate of 1.7 mL min⁻¹.

Shimadzu GC-2025 gas chromatograph with FID detector (GC-FID) was employed for quantitative analysis of the starting materials and products using a (0.25 μm × 0.25 mm × 30 m) DB-1 column. Nitrogen gas was used as the carrier gas at a flow rate of 2.0 mL min⁻¹. The quantitative analyses were performed by comparing the peak area of the products with known amount of nonane or dodecane as an internal standard. Calibration coefficient was determined by analyzing the mixtures of MO and the internal standard with different ratios. The amount of MO was calculated by normalization using the internal standard method with the calibration coefficient. The conversion of MO was obtained from the comparison of peak areas before and after reactions.

Self-metathesis reaction of methyl oleate (MO)

Typical procedure (run 2, Table 1) is as follows. Methyl oleate (MO, 0.593 g, 2.00 mmol) and dodecane (0.100 g) as an internal standard for GC analyses were dissolved in 1.0 mL of CH₂Cl₂ (DCM). Grubbs catalyst 2nd generation RuCl₂(PCy₃)(H₂IMes)(CHPh) (2) (0.0085 g, 0.5 mol%, 0.010 mmol) was added into the solution. The mixture was stirred at 50 °C for 1 hour, and then the resulting mixture was filtered through a Celite pad. The obtained filtrate was analyzed using the gas chromatograph with FID detector (GC-FID) and the gas chromatograph mass spectrometer (GC/MS). The results of self-metathesis reactions are summarised in Table 1.

Cross-metathesis reaction of methyl oleate (MO) with olefins

Typical procedure (run 11, Table 2) is as follows. Methyl oleate (MO, 0.593 g, 2.00 mmol), cis-4-octene (CO, 0.224 g, 2.00 mmol) and nonane (0.100 g) as an internal standard for GC analyses were dissolved in 1.0 mL of CH₂Cl₂ (DCM). Grubbs catalyst 2nd generation RuCl₂(PCy₃)(H₂IMes)(CHPh) (2) (0.0085 g, 0.5 mol%, 0.010 mmol) was added into the solution. The mixture was stirred at 50 °C for 1 hour, and then the resulting mixture was filtered through a Celite pad. The obtained filtrate was analyzed using the gas chromatograph with FID detector (GC-FID) and the gas chromatograph mass spectrometer (GC/MS). The results of cross-metathesis reactions are summarised in Tables 2 and 3.

Acknowledgements

W. A. acknowledges to Tokyo Metropolitan University (TMU), Tokyo Metropolitan government (Asian Human Resources Fund) for a fellowship of co-tutorial program between TMU and Universiti Kebangsaan Malaysia (UKM). We also appreciate a partial support from UKM for a preliminary study at UKM (FRGS/2/2014/ST01/UKM/1). B. H. expresses her thanks to IAESTE (The International Association for the Exchange of Students for Technical Experience) for the internship program. The project was partly supported by an international joint research program (sponsored by TMU) and the advanced research program (Tokyo Metropolitan government). Authors express their thanks to Profs. S. Komiya and A. Inagaki (TMU) for discussions.

Notes and references

1. For example, (a) Handbook of Metathesis, ed. R. H. Grubbs, Wiley-VCH, Weinheim, Germany, 2003; (b) Olefin Metathesis: Theory and Practice, ed. K. Grela, John Wiley & Sons, Inc, Hoboken, New Jersey, USA, 2014; (c) Handbook of Metathesis, ed. R. H. Grubbs and A. G. Wenzel, Wiley-VCH, Weinheim, Germany, 2nd edn, 2015, vol. 1.
2. For example, (a) A. Fürstner, Angew. Chem., Int. Ed., 2000, 39, 3012; (b) T. M. Trnka and R. H. Grubbs, Acc. Chem. Res., 2001, 34, 18; (c) R. R. Schrock and A. H. Hoveyda, Angew. Chem., Int. Ed., 2003, 42, 4592; (d) A. K. Chatterjee, in Handbook of Metathesis, ed. R. H. Grubbs, Wiley-VCH, Weinheim, Germany, 2003, vol. 2, p. 246; (e) C. Samojzowicz, M. Bieniek and K. Grela, Chem. Rev., 2009, 109, 3708; (f) G. Vougioukalakis and R. H. Grubbs, Chem. Rev., 2010, 110, 1746; (g) S. Monfette and D. Fogg, Chem. Rev., 2009, 109, 3783.
3. (a) U. Biermann, U. Bornscheuer, M. A. R. Meier, J. O. Metzger and H. J. Schäfer, Angew. Chem., Int. Ed., 2011, 50, 3854; (b) L. M. de Espinosa and M. A. R. Meier, in Organometallics and Renewables, ed. M. A. R. Meier, B. M. Weckjusen and P. C. A. Bruijnincx, Springer-Verlag, Berlin Heidelberg, Germany, 2012, p. 1; (c) A. Nickel and R. L. Pederson, in Olefin Metathesis: Theory and Practice, ed. K. Grela, John Wiley & Sons, Inc, Hoboken, New Jersey, USA, 2014, p. 335; (d) J. H. Philips, in Handbook of Metathesis, ed. R. H. Grubbs, A. G. Wenzel, D. J. O'Leary and E. Khosravi, Wiley-VCH, Weinheim, Germany, 2nd edn, 2015, vol. 3, p. 357; (e) M. A. R. Meier, Macromol. Chem. Phys., 2009, 210, 1073.
4. For examples (Jatropha bio-diesel production and use), W. M. J. Achten, L. Verchot, Y. J. Franken, E. Mathijs, V. P. Singh, R. Aerts and B. Muys, Biomass Bioenergy, 2008, 32, 1063.
5. Self metathesis and ethenolysis of unsaturated fatty acid esters (exemplified by methyl oleate, MO), (a) K. A. Burdett, L. D. Harris, P. Margl, B. R. Maughon, T. Mokhtar-Zadeh, P. C. Saucier and E. P. Wasserman, Organometallics, 2004, 23, 2027; (b) G. S. Forman, A. E. McConnell, M. J. Hanton, A. M. Z. Slawin, R. P. Tooze, W. J. van Rensburg, W. H. Meyer, C. Dwyer, M. M. Kirk and D. W. Serfontein, Organometallics, 2004, 23, 4824; (c) C. Thurier, C. Fischmeister, C. Bruneau, H. Olivier-Bourbigou and P. H. Dixneuf, ChemSusChem, 2008, 1, 118; (d) D. R. Anderson, T. Ung, G. Mkrtumyan, G. Bertland, R. H. Grubbs and Y. Schordi, Organometallics, 2008, 27, 563; (e) Y. Schordi, T. Ung, A. Vargas, G. Mkrtumyan, C. W. Lee, T. M. Champagne, R. L. Pederson and S. H. Hong, Clean: Soil, Air, Water, 2008, 36, 669; (f) S. C. Marinescu, R. R. Schrock, P. Müller and A. H. Hoveyda, J. Am. Chem. Soc., 2009, 131, 10840; (g) H. Mutlu, R. Hofsäβ, R. E. Montenegro and M. A. R. Meier, RSC Adv., 2013, 3, 4927; (h) A. Nickel, T. Ung, G. Mkrtumyan, J. Uy, C. W. Lee, D. Stoianova, J. Papazian, W.-H. Wei, A. Mallari, Y. Schrodi and R. L. Pederson, Top. Catal., 2012, 55, 518.
6. Examples for cross metathesis of unsaturated fatty acid esters (MO), (a) T. Jacobs, A. Rybak and M. A. R. Meier, Appl. Catal., A, 2009, 353, 32; (b) U. Biermann, M. A. R. Meier, W. Butte and J. O. Metzger, Eur. J. Lipid Sci. Technol., 2011, 113, 39; (c) X. Miao, R. Malacea, C. Fischmeister, C. Bruneau and P. H. Dixneuf, Green Chem., 2011, 13, 2911; (d) A. Behr and J. P. Gomes, Beilstein J. Org. Chem., 2011, 7, 1; (e) M. Abbas and C. Slugovc, Monatsh. Chem., 2012, 143, 669; (f) A. Kajetanowicz, A. Sytniczuka and K. Grela, Green Chem., 2014, 16, 1579; (g) M. Winkler and M. A. R. Meier, Green Chem., 2014, 16, 3335; (h) G. A. Abel, K. O. Nguyen, S. Viamajala, S. Varanasiac and K. Yamamoto, RSC Adv., 2014, 4, 55622.
7. For examples,^2d (a) H. E. Blackwell, D. J. O'Leary, A. K. Chatterjee, A. R. Washenfelder, D. A. Bussmann and R. H. Grubbs, J. Am. Chem. Soc., 2000, 122, 58; (b) A. K. Chatterjee, J. P. Morgan, M. Scholl and R. H. Grubbs, J. Am. Chem. Soc., 2000, 122, 3783; (c) A. K. Chatterjee, D. P. Sanders and R. H. Grubbs, Org. Lett., 2002, 4, 1939. Synthesis of symmetrical trisubstituted olefins by CM. Synthesis of functionalized olefins by CM and RCM; (d) A. K. Chatterjee, F. D. Toste, T.-L. Choi and R. H. Grubbs, Adv. Synth. Catal., 2002, 344, 634; (e) A. K. Chatterjee, T.-L. Choi, D. P. Sanders and R. H. Grubbs, J. Am. Chem. Soc., 2003, 125, 11360. A general model for selectivity in olefin cross metathesis; (f) I. C. Stewart, C. J. Douglas and R. H. Grubbs, Org. Lett., 2008, 10, 441. Increased efficiency in CM reactions of sterically hindered olefins; (g) M. L. Macnaughtan, J. B. Gary, D. L. Gerlach, M. J. A. Johnson and J. W. Kampf, Organometallics, 2009, 28, 2880. Scope and limitation of CM of vinyl halides; (h) H. Bilel, N. Hamdi, F. Zagrouba, C. Fischmeister and C. Bruneau, RSC Adv., 2012, 2, 9584 CM of eugenol, O-protected eugenol derivatives and ortho-eugenol with electron deficient olefins (methacrylate, acrylonitrile and acrylamides).
8. Effect of substituent on the 1,2-disubstituted olefins in cross metathesis polymerization (chain transfer) during acyclic diene metathesis polymerization using Ru(2) catalyst, T. Miyashita and K. Nomura, Macromolecules, 2016, 49, 518.

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Footnotes

† Electronic supplementary information (ESI) available: (i) General procedure and analysis data for their identifications and metathesis experiment, (ii) calculations of yield, conversion and selectivity, and (iii) GC-FID and GC-MS chromatogram. See DOI: 10.1039/c6ra24200f

‡ Present address: Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Vazovova 5, 812 43 Bratislava 1, Slovakia.

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