The carbon atom ring-insertion via pyrolysis of an α-diazo-β-hydroxy ester intermediate, in turn obtained by reaction between ethyldiazoacetate and 3,4-O-isopropylidene-3(R),4(S)-dihydroxycyclohexanone 2, a chiron easily prepared through a five step sequence from D(-)-quinic acid 1, was the key step for the construction of the cycloheptanone derivative 8. Its transformation into azidosulfate 18 set the stage for the preparation of the N-protected 8-azabicyclo[3.2.1]octane derivative 22, which, to the best of our knowledge, has been never obtained in optically pure form, as well as the tropan-6α-ol 24, obtained by reduction with LiAlH4.
From (-)-quinic acid to 8-azabicyclo[3.2.1]octane framework: Preparation of an enantiopure tropan-6 alpha-ol
BARCO, Achille;BENETTI, Simonetta;DE RISI, Carmela;MARCHETTI, Paolo;POLLINI, Gian Piero;ZANIRATO, Vinicio
1999
Abstract
The carbon atom ring-insertion via pyrolysis of an α-diazo-β-hydroxy ester intermediate, in turn obtained by reaction between ethyldiazoacetate and 3,4-O-isopropylidene-3(R),4(S)-dihydroxycyclohexanone 2, a chiron easily prepared through a five step sequence from D(-)-quinic acid 1, was the key step for the construction of the cycloheptanone derivative 8. Its transformation into azidosulfate 18 set the stage for the preparation of the N-protected 8-azabicyclo[3.2.1]octane derivative 22, which, to the best of our knowledge, has been never obtained in optically pure form, as well as the tropan-6α-ol 24, obtained by reduction with LiAlH4.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
