Efficient, Stereoselective Synthesis of Oxazolo[3,2-<i>a</i>]pyrazin-5-ones: Novel Bicyclic Lactam Scaffolds from the Bicyclocondensation of 3-Aza-1,5-ketoacids and Amino Alcohols
作者:Josef R. Bencsik、Timothy Kercher、Michael O'Sulliva、John A. Josey
DOI:10.1021/ol030065h
日期:2003.7.1
[reaction: see text] The bicyclocondensation of 3-aza-1,5-ketoacids and amino alcohols furnished novel oxazolo[3,2-a]pyrazin-5-one scaffolds possessing angular, ring junction substituents in high yield with excellent levels of substrate-based diastereocontrol. Mild oxidation of serinol-derived scaffolds provided access to a new class of constrained dipeptide surrogates. Deprotection of the endocyclic
An efficient method for a stereoselective synthesis of optically pure N-Boc-3-arylpiperazines has been developed. After optimization of the protecting group strategy and experimental conditions, compounds were obtained via a highly stereoselective synthesis in up to 45% overall yield. This is a practical route to optically pure piperazines for medicinal chemistry. (c) 2012 Elsevier Ltd. All rights reserved.