STEREO- AND REGIOCONTROL OF ACYCLIC SYSTEMS VIA THE LEWIS ACID MEDIATED REACTION OF ALLYLIC STANNANES WITH ALDEHYDES

Article abstract of DOI:10.1016/0040-4020(84)80007-1

The reaction of crotyltrialkylstannanes (1) with aldehydes in the presence of BF3*OEt2 produces the corresponding erythro homoallyl alcohols (2) predominantly regardless of the geometry of the double bond. Further, the Lewis acid mediated reaction exhibits the enhanced Cram selectivity in comparison with other allylic organometallic reactions which proceed in the absence of Lewis acids.Use of AlCl3-i-PrOH as the Lewis acid entirely changes the reaction course; the linear adduct (12) is produced rather than the branched adduct (13).The reaction of 1-BF3*OEt2 system is applied to the short and stereoselective synthesis of the (+/-) Prelog-Djerassi lactonic acid (16) and (-) verrucarinolactone (19).