A systematic study of the cross-coupling capability of 4- and 5-substituted 2-phenylthiazoles under Stille conditions is presented. Two cross-coupling options were investigated: 1) combination of thiazolylstannanes with various aryl(hetaryl) halides and, 2) reaction of halothiazoles with PhSn(Bu)3 as coupling partner. The results obtained from the cross-coupling reactions on the 4- and 5-positions of the thiazole system were compared regarding the influence of the position of the halide (Br, I) and the Bu3Sn group on both coupling partners. A broad selection of aromatic and heteroaromatic halides was coupled in order to establish a general reactivity platform for this heterocyclic system.
A systematic study of the cross-coupling capability of the 4- and 5-positions of 2-phenylthiazoles and -oxazoles under Stille conditions is presented. The azoles were both applied as stannanes and as the halide component. The obtained results were compared regarding the position of the halide and Bu3Sn group. In order to establish a general reactivity platform for those heterocyclic systems, a broad variety of aromatic and heteroaromatic halides were coupled and some significant differences concerning the coupling properties of the investigated systems were observed.
reaction of thiazoleboronic esters under microwave conditions is presented. Boronic acid esters were prepared in the 4- and 5-position of the thiazole ring and subsequently cross-coupled with a number of different (hetero)aryl halides. Yields of the coupling process depended on the reactivity of the boronic acid at the particular position in the thiazole system, as hydrolysis and subsequent deboronation
A guideline for the arylation of positions 4 and 5 of thiazole via Pd-catalyzed cross-coupling reactions
作者:Johanna Hämmerle、Michael Schnürch、Naseer Iqbal、Marko D. Mihovilovic、Peter Stanetty
DOI:10.1016/j.tet.2010.07.081
日期:2010.10
The arylation of thiazoles in 4- and 5-position was investigated in detail. Suzuki-Miyaura and Stille cross-coupling reactions were tested using thiazoles either as halide or organometal species. The obtained results were critically compared to develop helpful guidelines for selection of the cross-coupling methodology with the best potential for good and reliable results for a given synthetic problem without the need for tedious optimization of reaction parameters. (C) 2010 Elsevier Ltd. All rights reserved.
Direct Arylation of Thiazoles on Water
作者:Gemma L. Turner、James A. Morris、Michael F. Greaney