Synthesis of Bryostatins. 1. Construction of the C(1)-C(16) Fragment

Article abstract of DOI:10.1021/jo00273a009

The synthesis of fragment AB of bryostatin 1 is described.Two aldol coupling reactions involving (i) chiral fragment A with achiral B and (ii) chiral fragment A1 with achiral A2 constitute crucial steps in which an external chiral boron reagent is used to control stereoselectivity in the creation of a new stereogenic center.This type of double asymmetric synthesis, although rarely precedented, provides a powerful means of stereocontrol over the fragment assembly.