Generation of acyclic chiral building blocks containing a quaternary stereocenter. Formal synthesis of alkaloids of the leuconolam-leuconoxine-mersicarpine group

Abstract

The stereocontrolled dialkylation at the carbonyl α-position of simple phenylglycinol-derived oxazolopiperidone lactams generates chiral scaffolds bearing a quaternary stereocenter, which are converted to acyclic quaternary stereocenter-containing chiral building blocks, such as 2,2-disubstituted 5-aminopentanols and 4,4-disubstituted O-protected 5-hydroxypentanoic acids and 5- hydroxypentanenitriles. The enantioselective synthesis of Kerr's intermediate, anadvanced synthetic precursor of the alkaloids of the leuconolam-leuconoxine-mersicarpine group, is reported from one of these aminopentanols