Stereospecific synthesis of 2,2,3-trisubstituted tetrahydroquinolines: application to the total syntheses of benzastatin E and natural virantmycin

摘要

An efficient methodology for the synthesis of 2,2,3-tri substituted tetrahydroquinolines has been developed, which involves the triphenylphosphine-CCl4-mediated stereospecific rearrangement of alpha,alpha-disubstituted indoline-2-methanols 15 to 2,2,3-trisubstituted tetrahydroquinolines 26. The rearrangement precursors 15 are readily prepared by the diastereoselective Grignard addition to 2-acylindolines 13. The total syntheses of (+)-benzastatin E (1) and natural virantmycin (2a) were accomplished utilizing this methodology. This rearrangement reaction might afford some chemical precedent for the biogenetic pathway of the benzastatin family. (C) 2005 Elsevier Ltd. All rights reserved.