Intramolecular Michael reaction of methyl (R)-6-(tert -butoxycarbonylamino)oxy-4-hydroxy-2-hexenoate, in turn obtained from tert -butyl (R)-3-hydroxy-4-pentenoate, paved the way to the synthesis of both enantiomers of 2-oxa-6-azabicyclo[3.3.0]octan-3-one (the Geissman-Waiss lactone), a precursor for necine bases. Key intermediates in this approach were represented by enantiomeric bicyclic lactones incorporating a [1,2]-oxazinane nucleus, which has been conveniently used to install the pyrrolidine framework of the target compounds through a synthetic scheme featuring the reduction of the nitrogen-oxygen bond and an intramolecular SN 2 reaction.
A new enantiodivergent synthesis of the Geissman-Waiss lactone
BARCO, Achille;BARICORDI, Nikla;BENETTI, Simonetta;DE RISI, Carmela;POLLINI, Gian Piero;ZANIRATO, Vinicio
2007
Abstract
Intramolecular Michael reaction of methyl (R)-6-(tert -butoxycarbonylamino)oxy-4-hydroxy-2-hexenoate, in turn obtained from tert -butyl (R)-3-hydroxy-4-pentenoate, paved the way to the synthesis of both enantiomers of 2-oxa-6-azabicyclo[3.3.0]octan-3-one (the Geissman-Waiss lactone), a precursor for necine bases. Key intermediates in this approach were represented by enantiomeric bicyclic lactones incorporating a [1,2]-oxazinane nucleus, which has been conveniently used to install the pyrrolidine framework of the target compounds through a synthetic scheme featuring the reduction of the nitrogen-oxygen bond and an intramolecular SN 2 reaction.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
