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Phosphonium Coupling in the Direct Bond Formations of Tautomerizable Heterocycles via C–OH Bond Activation
Author(s) -
Kang FuAn,
Sui Zhihua,
Murray William V.
Publication year - 2009
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200801004
Subject(s) - phosphonium , chemistry , combinatorial chemistry , phosphonium salt , nucleophile , salt (chemistry) , organic chemistry , catalysis
Since the original report in 2004, phosphonium coupling has emerged as a new, mild, efficient, chemoselective and versatile methodology for the direct C–C, C–N, C–O, and C–S bond formations of unactivated and unprotected tautomerizable heterocycles. Phosphonium coupling proceeds via C–OH bond activation of a tautomerizable heterocycle with a phosphonium salt (e.g., PyBroP), and subsequent functionalization with either a nucleophile through S N Ar displacement or an organometallic through transition‐metal‐catalyzed cross‐coupling. As the first direct bond formation via C–OH bond activation, phosphonium coupling offers a powerful and practical methodology that features operational simplicity, functionality compatibility, and broad substrate scope. Its attractive protecting‐group‐free direct bond formation involving a domino multiple‐step process in a single step provides unique and facile access to many biologically important heterocycles including macromolecules with sensitive functionalities (e.g., DNA, RNA and PNA building blocks). Consequently, the discovery of phosphonium coupling has finally enabled a single‐step transformation in nucleoside chemistry, which has been an unsolved synthetic challenge in the past half‐century. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)