Cobalt(I)-Mediated Intramolecular [2+2+2] Cocyclizations of (Methylenecyclopropyl)diynes as an Easy Access to Cyclopropanated Oligocycles

Enediynes with methylenecyclopropane moieties attached either through the three‐membered ring or the double bond smoothly underwent cobalt‐mediated [2+2+2] cocyclizations to give cyclopropane‐fused and spirocyclopropanated cobalt‐complexed tricyclo[7.3.0.02,6]dodeca‐1,6‐dienes (1,2,3,3a,4,6,7,8‐octa...

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Published inEuropean Journal of Organic Chemistry Vol. 2005; no. 14; pp. 3000 - 3007
Main Authors Schelper, Michael, Buisine, Olivier, Kozhushkov, Sergei, Aubert, Corinne, de Meijere, Armin, Malacria, Max
Format Book Review Journal Article
LanguageEnglish
Published Weinheim WILEY-VCH Verlag 01.07.2005
WILEY‐VCH Verlag
Subjects
Cobalt
Cyclization
Cyclopropanes
Enediynes
Metal template synthesis
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Summary:Enediynes with methylenecyclopropane moieties attached either through the three‐membered ring or the double bond smoothly underwent cobalt‐mediated [2+2+2] cocyclizations to give cyclopropane‐fused and spirocyclopropanated cobalt‐complexed tricyclo[7.3.0.02,6]dodeca‐1,6‐dienes (1,2,3,3a,4,6,7,8‐octahydro‐as‐indacenes) under relatively mild conditions in yields ranging from 31 to 94 % (6 examples). Electron‐withdrawing substituents at the acetylenic terminus of the precursor are essential for a successful oligocyclization. While diphenyloxyphosphinyl‐substituted enediynes provided tricyclo[7.3.0.02,6]dodeca‐1,6‐diene complexes as mixtures of two diastereomers in high yields, the analogous methoxycarbonyl‐substituted precursors gave only one diastereomer. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Bibliography:ArticleID:EJOC200500111
istex:03B2723C68A26385A447F090D030CFB443D753F1
For one of us (A. de M.), this is to be counted as Part 113 in the series "Cyclopropyl Building Blocks for Organic Synthesis". Part 112: F. Brackmann, D. S. Yufit, A. de Meijere, Synthesis 2005, in press; Part 111: F. Brackmann, M. Es-Sayed, A. de Meijere, Eur. J. Org. Chem. 2005, in press.
ark:/67375/WNG-R06F458X-T
Chem.
in press; Part 111: F. Brackmann, M. Es‐Sayed, A. de Meijere
Synthesis
Eur. J. Org.
2005
in press.
For one of us (A. de M.), this is to be counted as Part 113 in the series “Cyclopropyl Building Blocks for Organic Synthesis”. Part 112: F. Brackmann, D. S. Yufit, A. de Meijere
ISSN:1434-193X
1099-0690
DOI:10.1002/ejoc.200500111