title: A mild and efficient CH2-extrusion reaction for the enantiospecific synthesis of highly configurationally stable Tröger bases.
abstract: A novel CH2 -extrusion reaction leading to the transformation of ethano-Tröger bases into disubstituted methano derivatives is reported (yields up to 93 %). Under mild and metal-free oxidative conditions, a loss of CH2 and a ring contraction are provoked. Despite two bond cleavages at stereogenic nitrogen and carbon centers and a temporary rupture of the bicyclic structure, a very high enantiospecificity (es≥98 %) is observed for this unusual reaction.
authors.affiliation: Department of Organic Chemistry, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva 4 (Switzerland).
authors.forename: Sandip A
authors.initials: SA
authors.lastname: Pujari
authors.affiliation: Laboratory of Crystallography, University of Geneva, Quai Ernest Ansermet 24, 1211 Geneva 4 (Switzerland).
authors.forename: Céline
authors.initials: C
authors.lastname: Besnard
authors.affiliation: Department of Physical Chemistry, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva 4 (Switzerland).
authors.forename: Thomas
authors.initials: T
authors.lastname: Bürgi
authors.affiliation: Department of Organic Chemistry, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva 4 (Switzerland). jerome.lacour@unige.ch.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Lacour
keywords: configuration determination; enantioselectivity; heterocycles; ring contraction; stereochemistry