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Samarium Diiodide Induced Reactions of Cyclopropyl Ketones: Reductive Ring Cleavage and Dimerization Leading to 1,8‐Diketones – Scope, Limitations, Mechanisms
Author(s) -
Aulenta Francesca,
Hölemann Alexandra,
Reißig HansUlrich
Publication year - 2006
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.200500945
Subject(s) - chemistry , ketone , aryl , samarium , cyclopropane , samarium diiodide , ketyl , medicinal chemistry , alkyl , ring (chemistry) , stereochemistry , organic chemistry , benzophenone
Reactions of the samarium diiodide/HMPA complex with alkyl cyclopropyl ketones such as 3 , 5 , and 7 provided dimers incorporating a 1,8‐diketone moiety. The products 4 , 6 , and 8 were isolated in moderate to good yields. The aryl‐substituted cyclopropyl ketones afforded a broader product spectrum, which results from the attack of samarium intermediates to the aryl group. Cyclopropyl phenyl ketone ( 13 ) gave dimer 14 , where one cyclopropane ring was reductively cleaved, whereas the second one is still present. The reductive dimerization of cyclopropyl 2‐thienyl ketone ( 21 ) furnished the product 22 , which still contains two cyclopropyl groups. Further examples demonstrate the diversity of samarium diiodide induced reductions of cyclopropyl ketones. Plausible reaction mechanisms involving samarium ketyl intermediates are presented.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)