An expedient synthesis of epi-eburnamenine via an intramolecular 1,4-dipolar cycloaddition reaction
作者:Albert Padwa、Mark A. Semones
DOI:10.1016/0040-4039(95)02166-3
日期:1996.1
The intramolecular1,4-dipolarcycloaddition of an anhydro-4-hydroxy-2-oxo-1,3-thiazium hydroxide across a tethered indole π-bond has been used for the construction of the pentacyclic skeleton of epi-16,17-dihydroeburnamenine.
Cycloaddition Reaction of Mesoionic Betaines as an Approach toward Trialkylindoline Alkaloids
作者:Albert Padwa、Scott R. Harring、Mark A. Semones
DOI:10.1021/jo970847m
日期:1998.1.1
cross-conjugated heteroaromaticbetaine. This 1,4-dipole undergoes a subsequent intramolecular dipolar cycloaddition across the neighboring pi-bond, and the resulting cycloadduct is subsequently converted to the annulated lactam. A related annulation sequence leading to a key intermediate previously utilized in the synthesis of the (+/-)-vallesamidine has been developed which is based on the intramolecular dipolar