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Desymmetrization of N ‐Sulfonated Aziridines by Alkyllithium Reagents in the Presence of Chiral Ligands
Author(s) -
Müller Paul,
Riegert David,
Bernardinelli Gérald
Publication year - 2004
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200490010
Subject(s) - chemistry , sulfonamide , enantioselective synthesis , sparteine , carbene , bicyclic molecule , allylic rearrangement , absolute configuration , rearrangement reaction , stereochemistry , sulfonyl , medicinal chemistry , organic chemistry , catalysis , alkyl
The stereochemical course of the rearrangement of the N ‐sulfonylaziridines 5, 15 , and 25 in the presence of s ‐BuLi/(−)‐sparteine to the bicyclic sulfonamides 4, 16 , and 17 , respectively, has been investigated chemically and by X‐ray structure analysis. The absolute configurations of the products were, in all cases, opposite to those of the alcohols formed upon rearrangement of the corresponding epoxides. Similarily, the allylic sulfonamide 10 , resulting from rearrangement of 7‐[(4‐methylphenyl)sulfonyl]‐7‐azabicyclo[4.1.0]heptane ( 7 ) under the same reaction conditions, had the ( R )‐configuration, while cyclohexen‐3‐ol, obtained upon rearrangement of cyclohexene oxide, is known to be ( S )‐configured. Deuterium labelling showed that the rearrangement of 7 proceeds via enantioselective α ‐elimination to a carbene, which undergoes a 1,2‐H shift.