Bridging the gap: Configurationallystable ethano‐bridged Trögerbases have been prepared in a single step by the direct rhodium(II)‐catalyzed reaction of methano‐bridged Trögerbases and diazo esters (see scheme). The process is general, enantiospecific, diastereoselective (with introduction of a new quaternary carbon center), and regioselective.
A Mild and Efficient CH<sub>2</sub>-Extrusion Reaction for the Enantiospecific Synthesis of Highly Configurationally Stable Tröger Bases
作者:Sandip A. Pujari、Céline Besnard、Thomas Bürgi、Jérôme Lacour
DOI:10.1002/anie.201500435
日期:2015.6.22
CH2‐extrusion reaction leading to the transformation of ethano‐Trögerbases 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 %)