Stereochemistry of C-6 nucleophilic displacements on 1, 1-difluorocyclopropyldibenzosuberanyl substrates. An improved synthesis of multidrug resistance modulator …

…, ME Kobierski, M Letourneau, TM Wilson

Index: Barnett, Charles J.; Huff, Bret; Kobierski, Michael E.; Letourneau, Michael; Wilson, Thomas M. Journal of Organic Chemistry, 2004 , vol. 69, # 22 p. 7653 - 7660

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Citation Number: 16

Abstract

Studies of the displacement chemistry of 1, 1-difluorocyclopropyldibenzosuberanyl alcohol 4 and its activated bromide derivative 6 have led to an improved approach to anti-2, a key precursor to LY335979 3HCl (1). Bromination of either syn-4 or anti-4 gave anti-oriented 6, indicating thermodynamically controlled product stereochemistry via a stabilized 1, 1- difluorohomotropylium ion intermediate. Reaction of 6 with piperazine proceeded ...