A new approach towards the synthesis of sp³ 1,1-diiodoalkanes

Abstract

An easy and straightforward method for the synthesis of gem-diiodo derivatives is reported.

References

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9. The LiAlH₄ was used as an ethereal solution which was titrated either by the iodometric method (H. Felkin, Bull. Soc. Chim. Fr., 1951, 18, 347) or with salicylaldehyde phenylhydrazone as indicator (B. E. Love and E. G. Jones, J. Org. Chem., 1999, 64, 3755).
10. Experimental procedure: To a suspension of AlCl₃(0.66 g, 4.95 mmol, 1.65 equiv.) in 3 ml of pentane and 7.5 ml of Et₂O was added an ethereal solution of LiAlH₄(1.09 M, 1.51 ml, 1.65 mmol, 0.55 equiv.) at room temperature. After stirring for 5 min, the solvents were removed at room temperature under vacuum (20 mmHg) through CaCl₂ to give a white suspension of LiCl and HAlCl₂(6.6 mmol, 2.2 equiv.). 6 ml of toluene was then added, followed by dec-1-yne (0.415 g, 3 mmol, 1 equiv.). The reaction mixture was heated at 90 °C for 3 h to give the 1,1-bis(di-chloroalumino)decane. After cooling to 0 °C, 20 ml of THF was added and a solution ofI₂(1.675 g, 6.6 mmol, 2.2 equiv.) in 20 ml of cold THF was then added. The reaction mixture was allowed to warm to room temperature and stirred for 15 min. The reaction mixture was then transferred into a cold solution (0 °C) of aqueous HCl (1 M, 100 ml). After stirring for 5 min, the aqueous layer was extracted with Et₂O, the collected organic phases were washed with aq.Na₂S₂O₃ and saturated brine, and then dried over MgSO₄. After filtration and evaporation of the solvents, the residue was chromatographed on silica gel.