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Enantio‐ and Diastereoselective Synthesis of Highly Substituted Acylcyclopropanes from Homoaldol Products by Stereospecific Homoallylic Cyclization
Author(s) -
Kalkofen Rainer,
Brandau Sven,
Ünaldi Seda,
Fröhlich Roland,
Hoppe Dieter
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.200500283
Subject(s) - chemistry , stereospecificity , alkoxide , intramolecular force , sodium hydride , stereochemistry , oxygen atom , enantioselective synthesis , hydride , medicinal chemistry , catalysis , molecule , organic chemistry , metal
Highly enantioenriched 4‐hydroxy‐1‐alkenyl N , N ‐diisopropylcarbamates, easily available by asymmetric homoaldol reaction, cyclize by treatment with sodium hydride to form (1 r ,2 t ,3 t )‐configured 1‐acylcyclopropanes with high diastereoselectivity. The decisive steps are the migration of the N , N ‐diisopropylcarbamoyl group onto the alkoxide oxygen atom, followed by an intramolecular homoallylic substitution reaction of the intermediate γ‐carbamoyloxy enolate with inversion of the configuration at the γ‐C atom. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)