Selectivity Control in Lewis Acid Catalyzed Regiodivergent Tandem Cationic Cyclization/Ring Expansion Terminated by Pinacol Rearrangement
作者:Lu Liu、Junliang Zhang
DOI:10.1002/anie.200901628
日期:2009.8.3
Catalyst is key: The title reaction sequence has been carried out on 1 in the presence of AgSbF6 (5 mol %) in DCE or In(OTf)3 (5 mol %) with MeOH (4 equiv) to afford 2 or 3, respectively, in up to >20:1 ratio (see scheme; DCE=1,2‐dichloroethane, Tf=trifluoromethanesulfonyl).