Volume 58, Issue 8 pp. 2500-2504
Communication

Cobalt-Catalyzed Intermolecular [2+2] Cycloaddition between Alkynes and Allenes

Dr. Wei Ding

Dr. Wei Ding

Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371 Singapore

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Prof. Naohiko Yoshikai

Corresponding Author

Prof. Naohiko Yoshikai

Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371 Singapore

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First published: 07 January 2019
Citations: 44

Graphical Abstract

In equal measure: A cobalt/diphosphine catalyst promotes a selective [2+2] cycloaddition reaction between an alkyne and an allene, affording a 3-alkylidenecyclobutene with high regioselectivity. The reaction tolerates various internal alkynes, and mono- and disubstituted allenes with different functional groups, and can be achieved using a near equimolar mixture of the unsaturated reactants.

Abstract

An intermolecular [2+2] cycloaddition reaction between an alkyne and an allene is reported. In the presence of a cobalt(I)/diphosphine catalyst, a near equimolar mixture of the alkyne and allene is converted into a 3-alkylidenecyclobutene derivative in good yield with high regioselectivity. The reaction tolerates a variety of internal alkynes and mono- or disubstituted allenes bearing various functional groups. The reaction is proposed to involve regioselective oxidative cyclization of the alkyne and allene to form a 4-alkylidenecobaltacyclopentene intermediate, with subsequent C−C reductive elimination.

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