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Regio‐ and Stereochemical Studies on the Nitroso‐Diels–Alder Reaction with 1,2‐Disubstituted Dienes
Author(s) -
Galvani Gilles,
Lett Robert,
Kouklovsky Cyrille
Publication year - 2013
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.201302905
Subject(s) - regioselectivity , steric effects , chemistry , nitroso , reagent , nitroso compounds , diene , diels–alder reaction , selectivity , medicinal chemistry , organic chemistry , stereochemistry , catalysis , natural rubber
The regioselectivity of the nitroso‐Diels–Alder reaction between unsymmetrical acyclic dienes and Boc‐nitroso (Boc= tert ‐butoxycarbonyl) reagent or the Wightman chiral chloronitroso reagents has been studied. With the Boc‐nitroso reagent, the selectivity is a consequence of steric effects at the C1‐position in the diene and electronic effects at the C2‐position in the diene. The combination of an unprotected hydroxyethyl side chain at C1 and an electron‐withdrawing group at C2 allows complete regioselectivity in favour of the proximal isomer. The same isomer was obtained exclusively with the chiral nitroso reagent with high enantioselectivities. A model based on steric effects is proposed.