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A New Access to Multifunctional Linear Triquinanes and Their Homologues via α,β‐Unsaturated Fischer Carbene Complexes
Author(s) -
Wu YaoTing,
Vidovic Denis,
Magull Jörg,
de Meijere Armin
Publication year - 2005
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200400858
Subject(s) - chemistry , carbene , tricyclic , ring (chemistry) , ring strain , yield (engineering) , dehydration , stereochemistry , ring size , catalysis , medicinal chemistry , organic chemistry , biochemistry , materials science , metallurgy
Twelve differently substituted tricyclic hydroxy ketones 7 , 8 with [5‐5‐ x ] ( x = 5, 6, 7) combinations of ring sizes were prepared in a single step in 43–91 % yields (10 examples with 74–91 %) from the corresponding protected (2'‐oxocycloalkyl)methyl‐substituted cyclopentadienes 6 , which were obtained by cocyclization of the alkynes 5 with the β‐dimethylamino‐substituted α,β‐unsaturated Fischer carbene complexes 4 in 38–81 % yield (6 examples with 66–81 %). In most cases, the cis , anti , cis ‐isomers anti ‐ 7 were the major products. While the twofold cis ‐fusion is favored by minimal ring strain, hydrogen bonding between the hydroxy and the carbonyl group probably favors the anti ‐configuration of the tricyclic skeletons. Acid‐catalyzed dehydration of the hydroxy ketones anti ‐ 7aa , anti ‐ 7ba , anti ‐ 7ca afforded the corresponding tricyclic dienes 15aa / 16aa , 15ba , and 15ca / 16ca , respectively. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)