104883-15-0Relevant articles and documents
Olivanic Acid Analogues. Part 2. Total Synthesis of Some C(6)-Substituted 7-Oxo-1-azabicyclohept-2-ene-2-carboxylates
Bateson, John H.,Quinn, Alison M.,Smale, Terence C.,Southgate, Robert
, p. 2219 - 2234 (2007/10/02)
A number of 6-substituted 7-oxo-1-azabicyclohept-2-ene-2-carboxylates related to the olivanic acids were prepared from the phosphorane (32).Generation of the anion α to the azetidin-2-one carbonyl group, followed by reaction with electrophiles and intramolecular cyclisation using the Wittig procedure gave the bicyclic products; in all cases the thermodynamically favoured trans-stereochemisty about the azetidinone ring predominated.In contrast, some less readily available cis-substituted analogues were obtained from the cyclohexa-1,4-diene derived phosphorane (61).The synthetic utility of a masked acetonyl ester group for preparing the free acids of these azabicycloheptene ring systems is described.