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Enantioselective Binaphthophosphepine‐Promoted [3+2] Annulations of N ‐Ts‐ and N ‐DPP‐Imines with Allenoates and 2‐Butynoates
Author(s) -
Pinto Nathalie,
FleuryBrégeot Nicolas,
Marinetti Angela
Publication year - 2009
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200800598
Subject(s) - chemistry , enantioselective synthesis , imine , enantiomer , reactivity (psychology) , catalysis , enantiomeric excess , medicinal chemistry , organic chemistry , stereochemistry , combinatorial chemistry , medicine , alternative medicine , pathology
The use of binaphthophosphepine 1a as a catalyst for the [3+2] cyclisation between allenoates or 2‐butynoates andimines was investigated. The effects of the imine protecting group on both the catalytic activity and enantioselectivity were determined by comparing the behaviour of N ‐tosyl‐ and N ‐DPP‐imines. The N ‐DPP‐imines displayed lower reactivity, but afforded the desired pyrrolines in higher enantiomeric excess (73–92 % ee ). The DPP protecting group was removed from the final pyrrolines under mild conditions to afford the corresponding secondary amines. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)