A Pd(0)-Mediated Indole (Macro)cyclization Reaction
作者:Steven P. Breazzano、Yam B. Poudel、Dale L. Boger
DOI:10.1021/ja3121394
日期:2013.1.30
Herein we report a systematic study of the Larock indole annulation designed to explore the scope and define the generality of its use in macrocyclization reactions, its use in directly accessing the chloropeptin I versus II DEF ring system as well as key unnatural isomers, its utility for both peptide-derived and more conventional carbon-chain based macrocycles, and its extension to intramolecular cyclizations with formation of common ring sizes. The studies define a powerful method complementary to the Stile or Suzuki cross-coupling reactions for the synthesis of cyclic or macrocyclic ring systems containing an embedded indole, tolerating numerous functional groups and incorporating various (up to 28-membered) ring sizes. As a result of the efforts to expand the usefulness and scope of the reaction, we also disclose a catalytic variant of the reaction, along with a powerful Pd-2(dba)(3)-derived catalyst system, and an examination of the factors impacting reactivity and catalysis.
Total Synthesis of Chloropeptin II (Complestatin) and Chloropeptin I
作者:Joie Garfunkle、F. Scott Kimball、John D. Trzupek、Shinobu Takizawa、Hiroyuki Shimamura、Masaki Tomishima、Dale L. Boger
DOI:10.1021/ja907193b
日期:2009.11.11
The first totalsynthesis of chloropeptinII (1, complestatin) is disclosed. Key elements of the approach include the use of an intramolecular Larock indole synthesis for the initial macrocyclization, adopting conditions that permit utilization of a 2-bromoaniline, incorporating a terminal alkyne substituent (-SiEt(3)) that sterically dictates the indole cyclization regioselectivity, and benefiting
Total Synthesis of Complestatin: Development of a Pd(0)-Mediated Indole Annulation for Macrocyclization
作者:Hiroyuki Shimamura、Steven P. Breazzano、Joie Garfunkle、F. Scott Kimball、John D. Trzupek、Dale L. Boger
DOI:10.1021/ja102304p
日期:2010.6.9
Full details of the initial development and continued examination of a powerful intramolecular palladium(0)-mediated indole annulation for macrocyclization closure of the strained 16-membered biaryl ring system found in complestatin (1, chloropeptin II) and the definition of factors impacting its intrinsic atropodiastereoselectivity are described. Its examination and use in an alternative, second-generation