Rhodium Carboxylate Catalyzed Decomposition of Vinyldiazoacetates in the Presence of Heterodienes: Enantioselective Synthesis of the 6-Azabicyclo[3.2.2]nonane and 6-Azabicyclo[3.2.2]nonanone Ring Systems
作者:Huw M. L. Davies、L. Mark Hodges
DOI:10.1021/jo025697g
日期:2002.8.1
catalyzed decomposition of vinyldiazoacetates in the presence of N-phenoxycarbonyl protected 1,2-dihydropyridines or 1-methyl-2-pyridones is a direct method for the construction of the 6-azabicyclo[3.2.2]nonane ring system. The [3 + 4] cycloaddition occurs by a tandem cyclopropanation/Cope rearrangement. Asymmetric induction is possible in these transformations either by using (S)-lactate methyl ester
Rhodium(II)-catalyzed decomposition of vinyldiazomethanes in the presence of 1,2-dihydropyridines: Synthesis of the 6-azabicyclo[3.2.2]nonane nucleus
作者:Huw M.L. Davies、L.Mark Hodges、Craig T. Thornley
DOI:10.1016/s0040-4039(98)00412-2
日期:1998.4
6-azabicyclo[3.2.2]nonadienes was synthesized via rhodium(II)-catalyzed decomposition of vinyldiazomethanes in the presence of substituted dihydropyridines. The regioselectivity of the reaction was shown to be highly dependent on the steric bulk of the catalyst as well as the structure of the vinyldiazomethane. Each regioisomer was elaborated into higher homologs of ferruginine (1, 2).
The enantioselective Diels Alder reaction of 1,2-dihydropyridines with aldehydes using an easily prepared optically active beta-amino alcohol catalyst was found to provide optically active isoquinuclidines, an efficient synthetic intermediate of pharmaceutically important compounds such as oseltamivir phosphate, with a satisfactory chemical yield and enantioselectivity (up to 96%, up to 98% ee). In addition, the obtained highly optically pure isoquinuclidine was easily converted to an optically active piperidine having four successive carbon centers.
Synthesis of 1-acyl-1,4-dihydropyridines via copper hydride reduction of 1-acylpyridinium salts