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.
Nonracemic ethano-bridged Tröger bases are prepared using CuTC-catalyzed decompositions of diazo compounds. Excellent levels of diastereo- and enantio-control (dr and ee up to 12 : 1 and 95% respectively) are now obtained with aryl diazoketone precursors.