Enolate formation from cyclopropyl ketones via iodide-induced ring openingand its use for stereoselective aldol reaction

Authors
Han, Z Uehira, S Tsuritani, T Shinokubo, H Oshima, K
Citation
Z. Han et al., Enolate formation from cyclopropyl ketones via iodide-induced ring openingand its use for stereoselective aldol reaction, TETRAHEDRON, 57(6), 2001, pp. 987-995
Citations number
30
Categorie Soggetti
Chemistry & Analysis","Organic Chemistry/Polymer Science
Journal title
TETRAHEDRON
ISSN journal
00404020 → ACNP
Volume
57
Issue
6
Year of publication
2001
Pages
987 - 995
Database
ISI
SICI code
0040-4020(20010204)57:6<987:EFFCKV>2.0.ZU;2-P
Abstract
Treatment of cyclopropyl ketones with TiCl4-n-Bu4NI mixed reagent provides (Z)-titanium enolates which afford syn-alpha -iodethyl-P-hydroxyketones ste reoselectively upon subsequent reaction with various aldehydes. The aldol a dducts are cyclized into transacyltetrahydrofurans in good yield by active alumina. In contrast, the nse of Et(2)AII in place of TiCl4-n-Bu4NI provide s the corresponding anti aldol adducts with high stereoselectivity. These m ethods can complementarily provide both syn and anti isomers of alpha -iodo ethyl-beta -hydroxyketones from cyclopropyl ketones and aldehydes. (C) 2001 Elsevier Science Ltd. All rights reserved.