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Addition of Grignard Reagents to Chiral 1,2‐Bisimines: A Diasteroselective Preparation of Unsymmetrical 1,2‐Diamines
Author(s) -
Roland Sylvain,
Mangeney Pierre
Publication year - 2000
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/(sici)1099-0690(200002)2000:4<611::aid-ejoc611>3.0.co;2-9
Subject(s) - chemistry , ethylamine , diastereomer , kinetic resolution , reagent , hydride , medicinal chemistry , stereoselectivity , chloride , reactivity (psychology) , organic chemistry , enantiomer , iminium , enantiomeric excess , chiral derivatizing agent , grignard reaction , glyoxal , enantioselective synthesis , catalysis , hydrogen , chiral column chromatography , medicine , alternative medicine , pathology
A diastereoselective synthesis of tert ‐butyl‐1,2‐diamines has been developed from the addition of tert ‐butylmagnesium chloride to the 1,2‐bisimines derived from glyoxal and chiral amines such as 1‐( S )‐ethylphenylamine, 1‐( S )‐phenylpropylamine or 1‐( S )‐( p ‐chlorophenyl)ethylamine. The influence of solvent, temperature and chiral auxiliaries on the chemical reactivity and stereoselectivity has been fully studied. Evidence of a dynamic kinetic resolution during the bis‐addition process of the organometallic, leading to the 1,2‐di‐ tert ‐butylethanediamine, [1] as a single diastereomer, has been demonstrated. This resolution has been applied with high diastereoselectivities to the synthesis of unsymmetrical disubstituted 1,2‐diamines, by addition of one equivalent of tert ‐butylmagnesium chloride, followed by one equivalent of a second Grignard reagent. Several chiral 1‐ tert ‐butyl‐1,2‐diamines have also been synthesized by monoaddition of tert ‐butylmagnesium chloride to the bisimines, followed by hydride reduction of the chiral intermediate imines.