Unprotected cis-2,3-diarylpiperidines are synthesized from readily available piperidines in only three operations. The key step is a palladium-catalyzed cross-coupling reaction between aryl halides and endocyclic 1-azallyl anions, elusive intermediates derived from the in situ deprotonation of 2-aryl-1-piperideines. This cross-coupling reaction can be achieved enantioselectively with a chiral mono-phosphine
仅通过三个操作即可从容易获得的
哌啶合成未保护的顺式-2,3-二芳基
哌啶。关键步骤是芳基卤化物和环内 1-氮杂
丙烯基阴离子之间的
钯催化交叉偶联反应,这是源自 2-芳基-1-
哌啶原位去质子化的难以捉摸的中间体。这种交叉偶联反应可以通过手性单
膦配体对映选择性地实现。