SYNTHESIS OF CHIRAL ORGANOTIN REAGENTS - SYNTHESIS OF BICYCLO[2.2.1]HEPTAN-2-YL(DIPHENYL)TIN HYDRIDES WITH CIS-DISPOSED, OXYGEN-CONTAINING SUBSTITUENTS

Alkylation of the methyl henylstannylbicyclo[2.2.1]hept-5-ene-2-carbox ylate 3 using lithium diethylamide and either methyl iodide or benzyl bromide at -78 degrees C is stereoselective in favour of the endo-alky lated products 10 and 11. Methylation of the saturated ester 12 is als o endo-selective in favour of 13, If the unsaturated ester 3 is deprot onated at 0 degrees C rather than at -78 degrees C, the rearranged sta nnane 17 is obtained as a side-product, The riphenylstannylbicyclo[2.2 .1]heptane-2-carboxylate 22 has been prepared from the ester 12 by phe nylselenylation, oxidative elimination and reduction using diimide, Th e triphenylstannanes 13, 17 and 20 have been converted into the alkyl( diphenyl)tin hydrides 27, 28 and 29 and the methoxyalkyltin hydride 36 has also been prepared and characterized, These tin hydrides accelera te the reduction of aryl methyl ketones to 1-arylethanols by phenylsil ane, but the reduction product is racemic, Syntheses of the aminobicyc loalkyl(triphenyl)stannanes 44, 45 and 48 are described.