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Synfacts 2013; 9(7): 0765
DOI: 10.1055/s-0033-1338905
Metal-Mediated Synthesis
© Georg Thieme Verlag Stuttgart · New York

Stereoselective Synthesis of All-Carbon Tetrasubstituted Alkenes

Contributor(s):
Paul Knochel
,
Nadja M. Barl
You W, Li Y, Brown MK * Indiana University, Bloomington, USA
Stereoselective Synthesis of All-Carbon Tetrasubstituted Alkenes from In Situ Generated Ketenes and Organometallic Reagents.

Org. Lett. 2013;
15: 1610-1613
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Further Information

Publication History

Publication Date:
17 June 2013 (online)

 
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Key words

lithium - magnesium - palladium - tetrasubstituted alkenes

Significance

The stereoselective synthesis of various all-carbon tetrasubstituted alkenes is disclosed, employing a two-step protocol which includes the stereoselective generation of an alkenyl pseudohalide followed by stereospecific palladium-catalyzed cross-coupling. The appropriate tetrasubstituted alkenes are obtained in good yield and with good diastereomeric ratios, providing mainly the Z-isomers.


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Comment

The reaction is proposed to proceed via a ketene intermediate which is stereospecifically attacked by a lithium organyl to form the trisubstituted enolate moiety attached to a pseudo-halide group [OTf or OP(P)(OR)2]. This moiety may be converted into other functional groups by palladium-catalyzed cross-couplings to give the corresponding all-carbon tetrasubstituted alkenes.


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