Enantio- and diastereoselective synthesis of syn-beta-functionalized homoallylic alcohols via aldehyde allylboration with [(Z)-gamma-(substituted)allyl]-10-TMS-9-borabicyclo[3.3.2]decane

ORGN 704

Jeremy Kister, jkister@scripps.edu and William R. Roush. Department of Chemistry, Scripps Florida, 130 Scripps Way, Jupiter, FL 33458
The enantio- and diastereoselective synthesis of syn-beta-functionalized homoallylic alcohols is a challenging task. In order to access this structural motif, we developed a new methodology for the preparation of (Z)-gamma-(substituted)allylboranes via a kinetically controlled hydroboration of mono-substituted allenes with 10-Trimethylsilyl-9-borabicyclo[3.3.2]decane (Soderquist borane). Reaction of these higer crotylborane reagents with aldehydes enables the formation of the targeted syn-beta-functionalized homoallylic alcohols with high enantio- (86-96% e.e.) and diastereoselective (90:10 to 94:6) control.