title: Origins of 1,6-stereoinduction in torquoselective 6π 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).
authors: Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1234, USA.
authors: Ashay
authors: A
authors: Patel
authors: Gregg A
authors: GA
authors: Barcan
authors: Ohyun
authors: O
authors: Kwon
authors: K N
authors: KN
authors: Houk
mesh_terms: D000959:Antihypertensive Agents / Q000138:chemical synthesis*; D003500:Cyclization; D004583:Electrons; D008958:Models, Molecular; D012110:Reserpine / Q000138:chemical synthesis*; D013237:Stereoisomerism
chemical_list: D000959:Antihypertensive Agents; D012110:Reserpine