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Norbornanoid Chiral Ketones by Desymmetrization of Dibromoalkenes
Author(s) -
Koçak Ramazan,
Borsato Giuseppe,
De Lucchi Ottorino,
Daştan Arif
Publication year - 2014
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.201300191
Subject(s) - chemistry , desymmetrization , norbornene , hydrolysis , steric effects , derivative (finance) , organic chemistry , isoprene , solvent , enantioselective synthesis , catalysis , polymer , monomer , copolymer , financial economics , economics
New optically active polycyclic ketones 6a – 6d , amenable to a large variety of synthetic applications, have been prepared from readily available 2,3‐dibromonorbornene and analogs ( Scheme 2 ) via desymmetrization with (−)‐ephedrine, followed by hydrolysis under mild acidic conditions. At variance with substrates 4a – 4d , the sterically hindered norbornene derivative 4e reacts with the solvent N ‐methylpyrrolidin‐2‐one (NMP) leading to the formation of the unusual cyclopropanoid products 8a and 8b .