Premium
Origin of Diastereocontrol in the Oxy‐Michael Reactions of δ‐Lactol Anions: A Computational and Experimental Study
Author(s) -
Richardson Robert D.,
HernandezJuan Felix A.,
Ward John W.,
Dixon Darren J.
Publication year - 2008
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200801368
Subject(s) - lactol , michael reaction , chemistry , organic chemistry , lactone , catalysis
The diastereoselectivity in the alkylation and Michael addition of “naked” 6‐substituted δ‐lactolates has been studied by density functional (B3LYP) calculations with ab initio (MP2) energy refinements. The resulting proposed model for the origins of stereocontrol in this reaction has been tested by experiment. The reactions lead to a high cis diastereoselectivity across the THP ring due to the preference for both the alkoxide and the 6‐substituent to sit equatorial in the alkylation transition structure. In the oxy‐Michael addition of these lactolates to β‐substituted nitroolefins, we propose that the high diastereoselectivity β‐ to the nitro group is a result of a combination of steric, stereoelectronic and solvation factors.