On the stereoselectivity of reaction between α-methylbut-2-enylstannanes and aldehydes

Abstract α-Methylbut-2-enylstannanes (7) - (9) react stereose1ective1y on heating with aldehydes to form anti -5-hydroxy-4-methyl- Z -pent-2-enes (16) and (17). In the presence of BF 3 · Et 2 O, the major products are the corresponding syn -5-hydroxy-4-methyl- E -pent-2-enes (22) and (23).