BETA-STANNYL ALLYLIC ALCOHOLS THROUGH PHOTOOXYGENATION (SCHENCK REACTION) OF VINYLSTANNANES AND REDUCTION OF THE RESULTING ALLYLIC HYDROPEROXIDES - SYNTHESIS AND SELECTED TRANSFORMATIONS

beta-Stannyl allylic alcohols 2 were prepared regioselectively by photooxygenation (Schenck reaction) of the vinylstannanes 1 and subsequent;reduction of the resulting allylic hydroperoxides by sodium borohydride. This novel methodology makes the hitherto unknown oxyfunctionalized cyclic vinylstannanes conveniently accessible, which constitute valuable building blocks in organic synthesis. For example, palladium-catalyzed coupling of these vinylstannanes 2 with allylic and vinylic halides produced the P-substituted allylic alcohols 3 in good yields. Tin-lithium exchange directly on the oxyfunctionalized vinylstannanes 2 afforded the corresponding lithio dianions, which on reaction with aldehydes led to the allylic diols 4. Furthermore, iododestannylation of the beta-stannyl allylic alcohols 2 gave the respective vinyl iodides 5.