Premium
Enantioselective Cycloadditions of 2‐Alkenoylpyridine‐ N ‐oxides Catalysed by a Bis(oxazoline)/Cu II Complex: Structure of the Reactive Intermediate
Author(s) -
Livieri Alessandro,
Boiocchi Massimo,
Desimoni Giovanni,
Faita Giuseppe
Publication year - 2011
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.201002017
Subject(s) - oxazoline , nitrone , chemistry , enantioselective synthesis , diene , absolute configuration , pyridine , derivative (finance) , oxide , stereochemistry , aryl , medicinal chemistry , reactive intermediate , cycloaddition , catalysis , organic chemistry , natural rubber , alkyl , financial economics , economics
Diels–Alder and 1,3‐dipolar cycloadditions involving ( E )‐3‐aryl‐1‐(pyridin‐2‐yl‐ N ‐oxide)prop‐2‐en‐1‐ones as the 2π components are efficiently catalysed by bis(oxazoline)–Cu II complexes. The cycloadducts are obtained in quantitative yields with up to 98 % ee ; absolute configurations were determined by X‐ray analysis. The structure of the reactive complex, determined by X‐ray analysis, is fully consistent with the stereochemical outcome of the catalysed process (approach of the diene or nitrone to the less hindered face of the coordinated pyridine‐ N ‐oxide derivative).