A straightforward route to enantiopure alpha-substituted derivatives of (2S,3aS,7aS)-octahydroindole-2-carboxylic acid.
High yielding and remarkably selective alkylations of a suitably protected derivative of (2S,3aS,7aS)-octahydroindole-2-carboxylic acid are described. The fused bicyclic structure of this proline analogue greatly influences the stereochemical outcome of direct alkylation reactions taking place at the alpha-carbon and provides access to alpha-substituted analogues with retention of the configuration. The overall procedure allows the preparation of enantiopure alpha-substituted derivatives of this Oic isomer, suitably protected for their incorporation into peptides, in a straightforward manner.
Sayago
Francisco J
FJ
Departamento de Química Orgánica, Instituto de Ciencia de Materiales de Aragón, Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain.
Calaza
M Isabel
MI
Jiménez
Ana I
AI
Cativiela
Carlos
C