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Origins of 1,6-stereoinduction in torquoselective 6? electrocyclizations.

ABSTRACT: A novel stereoselective electrocyclization developed for the total synthesis of reserpine has been explored by both experiment and theory. A stereocenter six atoms away from the newly forming chiral center is responsible for the diastereoselectivity of the ring closure. This stereogenic center, lying at the junction of two six-membered rings, defines the conformation of the substrates' fused ring skeleton that ultimately distinguishes between the two allowed, disrotatory triene geometries at the transition state. The presence of allylic strain in the disfavored transition state results in a torquoselective ring closure (dr up to 15.7:1).

SUBMITTER: Patel A

PROVIDER: S-EPMC3632451 | biostudies-literature | 2013 Mar

REPOSITORIES: biostudies-literature

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Origins of 1,6-stereoinduction in torquoselective 6π electrocyclizations.

Patel Ashay A Barcan Gregg A GA Kwon Ohyun O Houk K N KN

Journal of the American Chemical Society 20130318 12

A novel stereoselective electrocyclization developed for the total synthesis of reserpine has been explored by both experiment and theory. A stereocenter six atoms away from the newly forming chiral center is responsible for the diastereoselectivity of the ring closure. This stereogenic center, lying at the junction of two six-membered rings, defines the conformation of the substrates' fused ring skeleton that ultimately distinguishes between the two allowed, disrotatory triene geometries at the ...[more]

PMID: 23448287

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