Synthesis of chiral organotin reagents: synthesis of diphenyl- {(1S,2R,3S,4R)-3-(alkoxymethyl)bicyclo[2.2.1]heptan-2-yl}tin hydrides. X-Ray crystal structure of (R)-4,4-dimethyl-2-oxotetrahydrofuran-3-yl (1S,2S,3R,4R)-3-triphenylstannylbicyclo[2.2.1]hept-5-ene-2-carboxylate

Abstract

Conditions have been developed for the stereoselective Diels–Alder addition of cyclopentadiene to (R)-4,4-dimethyl-2-oxotetrahydrofuran-3-yl (E)-3-triphenylstannylprop-2-enoate 10 to give the endo-adduct 14 whose structure has been confirmed by X-ray crystallography. The adduct 14 is converted into (1S,2R,3S,4R)-3-hydroxymethylbicyclo[2.2.1]heptan-2-yl(triphenyl)stannane 22 which is shown to have an enantiomeric excess (ee) of 94%. This alcohol has been converted into its methyl ether (–)-3, trityl ether 25, tert-butyldimethylsilyl ether 26 and 1-naphthoate 27 which give the tin hydrides 4, 31–34 on treatment with iodine and sodium borohydride. Aspects of the chemistry of these enantiomerically enriched tin hydrides are briefly discussed.