Palladium-Catalyzed Cross-Coupling of Five-Membered Heterocyclic Silanolates
摘要:
The preparation of pi-rich 2-aryl heterocycles by palladium-catalyzed cross-coupling of sodium heteroarylsilanolates with aryl iodides, bromides, and chlorides is described. The cross-coupling process was developed through extensive optimization of the following key variables: (1) identification of stable, isolable alkali metal silanolates, (2) identification of conditions for preformation and isolation of silanolate salts, (3) judicious choice in the palladium catalyst/ligand combination, and (4) selection of the protecting group on the nitrogen of indole. It was found that the alkali metal silanolates, either isolated or formed in situ, offered a significant rate enhancement and broader substrate scope over the use of silanols activated by Bronsted bases such as NaOt-Bu. In addition, the optimized conditions for the cross-coupling of 2-indolylsilanolates were readily applied to the cross-coupling of 2-pyrrolyl-, 2-furyl-, and 2-thienylsilanolates.
Palladium-Catalyzed Cross-Coupling Reactions of 2-Indolyldimethylsilanols with Substituted Aryl Halides
作者:Scott E. Denmark、John D. Baird
DOI:10.1021/ol048328a
日期:2004.9.1
[reaction: see text] A mild and general cross-couplingreaction of 2-indolylsilanols has been developed. The experimental variables that lead to successful coupling are (1) the use of sodium tert-butoxide as the activator, (2) the use of copper(I) iodide in stoichiometric quantities, and (3) the use of Pd2(dba)3.CHCl3 as the catalyst. Under these conditions N-(Boc)-2-indolyldimethylsilanol reacts with
Palladium-Catalyzed Cross-Coupling of Five-Membered Heterocyclic Silanolates
作者:Scott E. Denmark、John D. Baird、Christopher S. Regens
DOI:10.1021/jo7023784
日期:2008.2.1
The preparation of pi-rich 2-aryl heterocycles by palladium-catalyzed cross-coupling of sodium heteroarylsilanolates with aryl iodides, bromides, and chlorides is described. The cross-coupling process was developed through extensive optimization of the following key variables: (1) identification of stable, isolable alkali metal silanolates, (2) identification of conditions for preformation and isolation of silanolate salts, (3) judicious choice in the palladium catalyst/ligand combination, and (4) selection of the protecting group on the nitrogen of indole. It was found that the alkali metal silanolates, either isolated or formed in situ, offered a significant rate enhancement and broader substrate scope over the use of silanols activated by Bronsted bases such as NaOt-Bu. In addition, the optimized conditions for the cross-coupling of 2-indolylsilanolates were readily applied to the cross-coupling of 2-pyrrolyl-, 2-furyl-, and 2-thienylsilanolates.
Practical and Selective Bio-Inspired Iron-Catalyzed Oxidation of Si–H Bonds to Diversely Functionalized Organosilanols
作者:Song Li、Haibei Li、Chen-Ho Tung、Lei Liu
DOI:10.1021/acscatal.2c02678
日期:2022.8.5
oxidant at an iron catalyst loading of 0.1 mol % is reported. The practical and highlyselective oxidation exhibits good functional group tolerance, allowing effective access to diverselyfunctionalized alkyl-, aryl-, alkynyl-, and alkoxysilanols, silanediols, as well as mono-, oligo-, and polymeric siloxanols with various substituent patterns. Late-stage gram-scale application in functional-molecule-containing