Deprotonative Magnesation and Cadmation of [1,2,3]Triazolo[1,5-<i>a</i>]pyridines
作者:Ghenia Bentabed-Ababsa、Fernando Blanco、Aïcha Derdour、Florence Mongin、François Trécourt、Guy Quéguiner、Rafael Ballesteros、Belén Abarca
DOI:10.1021/jo801675h
日期:2009.1.2
[1,2,3]Triazolo[1,5-a]pyridine and 3-substituted derivatives were regioselectively metalated at the 7 position using either Bu3MgLi or (TMP)3CdLi, the former at −10 °C and the latter at room temperature. The lithium arylmagnesates (R = H, Me, Ph) proved to react with iodine (34−75%) or 3,4,5-trimethoxybenzaldehyde (32−51%). Attempts to obtain the cross-coupling products using 2-bromopyridine under
使用Bu 3 MgLi或(TMP)3将[1,2,3]三唑并[1,5- a ]吡啶和3-取代的衍生物在7位区域选择性金属化CdLi,前者在-10°C下,而后者在室温下。芳基镁酸锂(R = H,Me,Ph)被证明与碘(34-75%)或3,4,5-三甲氧基苯甲醛(32-51%)反应。在钯催化下使用2-溴吡啶获得交叉偶联产物的尝试失败了,这归因于这些化合物的低稳定性。在相同的反应条件下,相应的芳基锌酸锂以17-60%的产率反应。芳基镉酸锂被碘(38-76%,R = H,Me,Ph,CN,2-噻吩基)捕获,或参与了钯催化的与2-溴吡啶的交叉偶联反应(26-67%,R = H,Me,Ph)。对于R = 2-吡啶基,以73%的产率分离出3-(6-碘-2-吡啶基)-[1,2,3]三唑并[1,5- a ]吡啶。(TMP)3CdLi还被证明适用于两种底物(R = H,2-噻吩基)的清洁双去质子化作用,碘淬灭(66-75%)证明了这一结果。