Spiroquinazoline support studies: methods for the preparation of imidazoloindolines from oxindoles

Two methods for the annulation of glycine to the I and 2 positions of oxindoles are described. The first method involves introduction of an alpha-azidoacetyl group on the oxindole nitrogen followed by an intramolecular Staudinger reaction to complete the annulation. The second method involves acylation of the oxindole nitrogen with an N-Cbz-glycine derivative followed by reduction of the oxindole carbonyl group and subsequent cyclization to provide an imidazoloindoline. (c) 2006 Elsevier Ltd. All rights reserved.