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Chiral N ‐Phosphonylimine Chemistry: Asymmetric Synthesis of N ‐Phosphonyl β‐Amino Weinreb Amides
Author(s) -
Kaur Parminder,
Nguyen Thao,
Li Guigen
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.200801061
Subject(s) - chemistry , deprotonation , lithium (medication) , enantioselective synthesis , optical rotation , stereochemistry , medicinal chemistry , chiral auxiliary , absolute configuration , organic chemistry , catalysis , ion , medicine , endocrinology
Various chiral N ‐phosphonyl β‐amino Weinreb amides were synthesized by treating chiral N ‐phosphonyl imines with the lithium enolate of N ‐methoxy‐ N ‐methylacetamide. The N , N ‐protection groups on chiral N ‐phosphonyl imines and the types of deprotonation bases for enolate generation were found to be crucial for the successful synthesis. Eleven Weinreb amides were obtained in excellent chemical yields (92 to 98 %) and good to excellent diastereoselectivities (up to dr = 99:1). The absolute structures were unambiguously determined by converting the products into authentic samples and by comparing their optical rotation values.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)