4. Vinylogous Mukaiyama Aldol Reactions with Triarylboranes
M. Christmann, M. Kalesse
The first vinylogous Mukaiyama aldol reactions with tris(pentafluorophenyl)borane and triphenylborane are described. Both Lewis acids diastereoselectively generate the C19–C21 all-syn stereo triad of ratjadone, and in the case of tris(pentafluorophenyl)borane the reaction proceeds with substoichiometric amounts.