A broad range of substituted 2-cyclopentenone derivatives 3-6 are synthesized by the nickel(0)-mediated [3 + 2] cyclization reaction of chromium alkenyl(methoxy)carbene complexes 1 and internal alkynes 2. The reaction takes place with complete regioselectivity with both unactivated alkynes and activated alkynes (electron-withdrawing and electron-donating substituted alkynes). Representative cycloadducts containing boron and tin substituents are further demonstrated to be active partners in classical Pd-catalyzed C-C coupling processes to allow the production of 2-aryl- and 2-alkynyl-substituted cyclopentenones 9-13.

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http://dx.doi.org/10.1021/ja075106+DOI Listing

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