New Methylene Homologation Method for Cyclic Ketones
作者:Huaqing Liu、Chunrui Sun、Nam-Kyu Lee、Roger F. Henry、Daesung Lee
DOI:10.1002/chem.201201346
日期:2012.9.17
Teaching new tricks to an old dog: By intercepting adducts between ketones and lithium trimethylsilyldiazomethane, a new Tiffeneau–Demjanov type methylenehomologation could be realized in a single‐step operation. Among proton sources and Lewis acids, silica gel was found to be the most effective reagent for the protonation of intermediates and their subsequent ring expansion (see scheme).