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Electronic Control of Product Distribution in the [5+5]-Coupling of ortho-Alkynylbenzaldehyde Derivatives and ?,?-Unsaturated Carbene Complexes.

ABSTRACT: The coupling of highly oxygenated ortho-alkynylbenzaldehyde derivatives with ?,?-carbene complexes was evaluated systematically. In all of the electron-rich systems investigated the exclusive product of the reaction is the dihydrophenanthrene derivative. Only the extremely electron withdrawing methanesulfonate group can prevent this process from occurring. The use of the base additive collidine resulted in a surprising yield enhancement but no other discernable effect on the course of the reaction. Dihydrophenanthrene formation was attributed to rapid dehydration after the opening of a benzo-oxanorbornene intermediate.

SUBMITTER: Camacho-Davila A

PROVIDER: S-EPMC2920532 | biostudies-literature | 2010 Jul

REPOSITORIES: biostudies-literature

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Electronic Control of Product Distribution in the [5+5]-Coupling of ortho-Alkynylbenzaldehyde Derivatives and γ,δ-Unsaturated Carbene Complexes.

Camacho-Davila Alejandro A Gamage Lalith S R LS Wang Zhipeng Z Herndon James W JW

Tetrahedron 20100701 27-28

The coupling of highly oxygenated ortho-alkynylbenzaldehyde derivatives with γ,δ-carbene complexes was evaluated systematically. In all of the electron-rich systems investigated the exclusive product of the reaction is the dihydrophenanthrene derivative. Only the extremely electron withdrawing methanesulfonate group can prevent this process from occurring. The use of the base additive collidine resulted in a surprising yield enhancement but no other discernable effect on the course of the reacti ...[more]

PMID: 20711418

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