Direct C7 Functionalization of Tryptophan. Synthesis of Methyl (S)-2-((tert-Butoxycarbonyl)amino)-3-(7-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-indol-3-yl)propanoate
Functionalization of Aromatic Amino Acids via Direct C−H Activation: Generation of Versatile Building Blocks for Accessing Novel Peptide Space
作者:Falco-Magnus Meyer、Spiros Liras、Angel Guzman-Perez、Christian Perreault、Jianwei Bian、Keith James
DOI:10.1021/ol1015674
日期:2010.9.3
Functionalized α-amino acid building blocks have been prepared in good yield with high regiocontrol and preservation of stereochemistry via iridium-catalyzed borylation of suitably protected aromatic α-amino acid derivatives. The utility of these systems in peptide couplings and Suzuki reactions has been demonstrated.
Synthesis of 2-D-L-tryptophan by sequential Ir-catalyzed reactions
作者:Ravikrishna Vallakati、Abel T. Plotnikov、Ryan A. Altman
DOI:10.1016/j.tet.2019.02.054
日期:2019.4
Herein, we report a practical synthesis of 2-D-l-tryptophan via sequential Ir-catalyzed CH borylation, and Ir-catalyzed C-2-deborylative deuteration steps. In this synthetic sequence, deprotection of the Boc and methyl ester groups proved challenging, due to replacement of deuterium with hydrogen. However, mild deprotection conditions were developed to avoid this D/H scrambling. Further, 2-D-L-Tryptophan
Bismuth Acetate as a Catalyst for the Sequential Protodeboronation of Di- and Triborylated Indoles
作者:Fangyi Shen、Sriram Tyagarajan、Damith Perera、Shane W. Krska、Peter E. Maligres、Milton R. Smith、Robert E. Maleczka
DOI:10.1021/acs.orglett.6b00356
日期:2016.4.1
Bismuth(III) acetate is a safe, inexpensive, and selective facilitator of sequential protodeboronations, which when used in conjunction with Ir-catalyzed borylations allows access to a diversity of borylated indoles. The versatility of combining Ir-catalyzed borylations with Bi(III)-catalyzed protodeboronation is demonstrated by selectively converting 6-fluoroindole into products with Bpin groups at
C7-Derivatization of C3-Alkylindoles Including Tryptophans and Tryptamines
作者:Richard P. Loach、Owen S. Fenton、Kazuma Amaike、Dustin S. Siegel、Erhan Ozkal、Mohammad Movassaghi
DOI:10.1021/jo502062z
日期:2014.11.21
A versatile strategy for C7-selective boronation of tryptophans, tryptamines, and 3-alkylindoles by way of a single-pot C2/C7-diboronationC2-protodeboronation sequence is described. The combination of a mild iridium-catalyzed C2/C7-diboronation followed by an in situ palladium-catalyzed C2-protodeboronation allows efficient entry to valuable C7-boroindoles that enable further C7-derivatization. The versatility of the chemistry is highlighted by the gram-scale synthesis of C7-boronated N-Boc-L-tryptophan methyl ester and the rapid synthesis of C7-halo, C7-hydroxy, and C7-aryl tryptophan derivatives.