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Recent Developments in the Metal‐Catalyzed Reactions of Metallocarbenoids from Propargylic Esters
Author(s) -
MarcoContelles José,
Soriano Elena
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.200601522
Subject(s) - cyclopropanation , cycloisomerization , intramolecular force , chemistry , enol , bicyclic molecule , chirality (physics) , intermolecular force , catalysis , stereochemistry , medicinal chemistry , organic chemistry , molecule , chiral symmetry breaking , physics , quantum mechanics , nambu–jona lasinio model , quark
Abstract The transition‐metal‐catalyzed intramolecular cycloisomerization of propargylic carboxylates provides functionalized bicyclo[ n .1.0]enol esters in a very diastereoselective manner and, depending on the structure, with partial or complete transfer of chirality from enantiomerically pure precursors. The subsequent methanolysis gives bicyclo[ n .1.0] ketones, hence resulting in a very efficient two‐step protocol for the syntheses of α,β‐unsaturated cyclopropyl ketones, key intermediates for the preparation of natural products. The results from mechanistic computational studies suggest that they probably proceed through cyclopropyl metallocarbenoids, formed by endo ‐cyclopropanation, that undergo a 1,2‐acyl migration. Finally, the potential of the intermolecular reaction and the related pentannulation of propargylic esters bearing pendant aromatic rings are also discussed.