68485-80-3

Upstream product

• 20205-48-5 8-oxo-7-azabicyclo<4.2.0>oct-2-ene 
• 68485-79-0 p-nitrobenzyl 8-oxo-7-azabicyclo<4.2.0>oct-3-en-7-yl(triphenylphosphoranylidene)acetate 
• 64370-35-0 p-nitrobenzyl glyoxylate 
• 68485-78-9 7-(1-Hydroxy-1-p-nitrobenzyloxycarbonylmethyl)-8-oxo-7-azabicyclo[4,2,0]-oct-3-ene 
• 75440-26-5 (5RS,6SR)-p-nitrobenzyl 6-formylmethyl-7-oxo-1-azabicyclo<3.2.0>hept-2-ene-2-carboxylate 
• 21204-67-1 methyl (triphenylphosphoranylidene)acetate 

Relevant academic research and scientific papers

Olivanic Acid Analogues. Part 2. Total Synthesis of Some C(6)-Substituted 7-Oxo-1-azabicyclohept-2-ene-2-carboxylates

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.