Published October 16, 1995
| public
Journal Article
Stereoselective Free-Radical Cycloaddition-Macrocyclization in Facile Synthesis of Trans-Cyclohexano-Fused 12-Membered Crown Thioethers
Chicago
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Abstract
Homolytic cycloaddition of dithiols 1,2 derived from trans- and eis-1,2-cyclohexanediols to alkynes, induced by Pr3B-O2, offers an extremely simple approach to trans- and cis-cyclohexano-fused 12-membered crown thialactones 4a-c-7a-c. The reaction of trans-1 proceeds with pronounced remote 1,6-asymmetric induction to give predominantly (IS *, 6R *, 12S *)-4a–c, while cis-2 reacts nonstereoselectively. Basing on molecular mechanics calculations the stereoselectivity is rationalized as a result of entropy favored pathway of macrocyclization.
Additional Information
Copyright © 1995 Published by Elsevier. (Received in UK 27 June 1995; revsed 25 August 1995; accepted 1 September 1995) We are grateful to Mr R Fleming (The University of Nottingham, U.K ) for recording several NMR (400 MHz) spectra We thank the InternatIonal Science Foundation (Soros Foundation) (Grant MPL 000) and Russian Foundation of Fundamental Studies (Projects 93-03-18110 and 94-03-09296) for generous financial support E.I.T. also indebtedly thanks the Royal Society for the Kapitza Fellowship and Professor Gerald Pattenden for very helpful discussion on macrocyclization. Dedicated to Professor Nikolay S. Zefirnv on the occasion of his 60th birthday.Additional details
- Eprint ID
- 40886
- Resolver ID
- CaltechAUTHORS:20130821-160734712
- International Science Foundation
- MPL000
- Russian Foundation for Fundamental Studies
- 93-03-18110
- Russian Foundation for Fundamental Studies
- 94-03-09296
- Royal Society
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2013-08-29Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field