Regio- and Stereoselective Cross-aldol Reactions via Dialkylboryl Triflates

Article abstract of DOI:10.1246/bcsj.53.174

New borylating reagents, (Bu2BOTf and 9-BBNOTf), were prepared in high yields.The triflates reacted with enolizable ketones in the presence of tertiary amines to generate selectively one of the regioisomers of vinyloxyboranes by the choice of the reagents (the dialkylboryl triflates and tertiary amines) under mild reaction conditions.Vinyloxyboranes thus generated showed remarkable reactivity toward aldehydes to give only one regioisomer of the corresponding cross-aldols in good yields.High stereoselectivity was also observed in these reactions.