163. A Mild and Efficient CH₂-Extrusion Reaction for the Enantiospecific Synthesis of Highly Configurationally Stable Tröger Bases
     Sandip A. Pujari, Céline Besnard, Thomas Bürgi, Jérôme Lacour
     Angew. Chem. Int. Ed. 2015, 54, 7520-7523

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.

DOI: 10.1002/anie.201500435 

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