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DOI: 10.1055/s-2008-1077971
Torquoselective Olefination of Carbonyl Compounds with Ynolates: Highly Efficient Stereoselective Synthesis of Tetrasubstituted Alkenes
Publication History
Received
26 February 2008
Publication Date:
15 July 2008 (online)


Abstract
The torquoselectivity-controlled olefination of carbonyl compounds with ynolates affording tetrasubstituted alkenes is described. The E/Z selectivity is determined in the step consisting of electrocyclic ring opening of the β-lactone enolates (oxetenes) derived from cycloaddition of ynolates with carbonyl compounds. Theoretical calculations revealed that several secondary orbital interactions are critical for the high torquoselectivity. This methodology is a novel olefination for constructing multisubstituted olefins.
1 Introduction
2 Preparation of Ynolates
3 Olefination of Aldehydes
4 Olefination of Unfunctionalized Ketones
5 Acylsilanes and Acylgermanes
5.1 Olefination of Acylsilanes
5.2 Olefination of Acylgermanes
5.3 Olefination of Acylsilanes and Acylgermanes via Stereoselective Protonation of β-Lactone Enolates, Followed by Decarboxylation
5.4 Organic Synthesis Using Multisubstituted Vinylsilanes
5.4.1 Oxidative Cleavage of C-Si Bonds
5.4.2 Reactions of Silalactones
5.4.3 Palladium-Catalyzed Cross Coupling Activated by Hypervalency
6 Heteroatom-Directed Torquoselective Olefination
7 Olefination of Esters
8 Olefination of Aldimines
9 Conclusion
Key words
electrocyclic ring opening - olefination - theoretical calculations - torquoselectivity - ynolates