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Copper‐Catalyzed Enantioselective Intramolecular Conjugate Addition/Trapping Reactions: Synthesis of Cyclic Compounds with Multichiral Centers
Author(s) -
Li Kangying,
Alexakis Alexandre
Publication year - 2007
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.200601327
Subject(s) - intramolecular force , conjugate , enantioselective synthesis , trapping , catalysis , chemistry , copper , combinatorial chemistry , stereochemistry , organic chemistry , mathematics , biology , mathematical analysis , ecology
The Cu‐catalyzed enantioselective conjugate addition of dialkylzinc to bis‐α,β‐unsaturated carbonyl compounds followed by the intramolecular trapping of the zinc enolate in the presence of chiral phosphoramidite ligands was investigated. Cyclic and heterocyclic compounds with multichiral centers were formed as a mixture of two diastereomers with excellent diastereoselectivities (up to 99:1) and enantioselectivities (up to 94 % ee , ee =enantiomeric excess). The stereochemistry was determined to be trans , trans for the major products and trans , cis for the minor products. The absolute configuration of the cyclic compounds was assigned by comparison with the analogous adduct derived from trans ‐3‐nonen‐2‐one and Et 2 Zn or the adduct obtained through conjugate addition of Me 2 Zn to trans ‐1‐phenyl‐non‐2‐en‐1‐one. Further transformation of these cyclic products into more complex compounds is under investigation in our laboratory.