Stereoselectivity in metal carbene and Lewis acid-catalyzed reactions from diastereomeric dirhodium(II) carboxamidates: Menthyl N-acetyl-2-oxoimidazolidine-4(S)-carboxylates
摘要:
The influence of a chiral menthyl group as the pendant ester substituent on the N-acetyl-2-oxoimidazolidine-4S-carboxylate ligands in chiral dirhodium(II) imidazolidinone catalysts has been examined. Significant match/mismatch influences are evident in the observed stereocontrol for carbon-hydrogen insertion reactions with diazoacetates, but these effects are minimal in cyclopropanation reactions. Steric restrictions prevent effective enantiocontrol in hetero-Diels-Alder reactions using these menthyl-substituted catalysts. (c) 2005 Elsevier B.V. All rights reserved.
Stereoselectivity in metal carbene and Lewis acid-catalyzed reactions from diastereomeric dirhodium(II) carboxamidates: Menthyl N-acetyl-2-oxoimidazolidine-4(S)-carboxylates
摘要:
The influence of a chiral menthyl group as the pendant ester substituent on the N-acetyl-2-oxoimidazolidine-4S-carboxylate ligands in chiral dirhodium(II) imidazolidinone catalysts has been examined. Significant match/mismatch influences are evident in the observed stereocontrol for carbon-hydrogen insertion reactions with diazoacetates, but these effects are minimal in cyclopropanation reactions. Steric restrictions prevent effective enantiocontrol in hetero-Diels-Alder reactions using these menthyl-substituted catalysts. (c) 2005 Elsevier B.V. All rights reserved.