475102-18-2Relevant articles and documents
Palladium-catalyzed cross-coupling of five-membered heterocyclic silanolates
Denmark, Scott E.,Baird, John D.,Regens, Christopher S.
, p. 1440 - 1455 (2008/04/12)
(Chemical Equation Presented) The preparation of π-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.
A non-cryogenic method for the preparation of 2-(indolyl) borates, silanes, and silanols
Vazquez, Enrique,Davies, Ian W.,Payack, Joseph F.
, p. 7551 - 7552 (2007/10/03)
2-Indolyl borates are prepared via addition of LDA to a mixture of N-Bo-indole and triisopropyl borate at 0-5 °C. Following acidic hydrolysis, the boronic acids are isolated by crystallization in good to excellent yield (73-99%). The method is quite general, tolerating a wide range of functional groups, and also provides access to 2-silyl derivatives (80-91%).