Multi-chelation approach towards natural product-like skeletons: one-pot access to a nitrogen-containing tetracyclic framework from AlaAla dipeptide

Abstract

Reductive transformation of the dipeptide BocAlaAlaOMe to a complex, internally charge-stabilized, natural product-like skeleton in one synthetic step is discussed. Stepwise replacement of the B–H bonds in borane by B–N or B–O resulted in incorporation of three boron atoms in a tetracyclic framework whereby one is stereogenic!