Structural complexity through multicomponent cycloaddition cascades enabled by dual-purpose, reactivity regenerating 1,2,3-triene equivalents
作者:Paul A. Wender、Dennis N. Fournogerakis、Matthew S. Jeffreys、Ryan V. Quiroz、Fuyuhiko Inagaki、Magnus Pfaffenbach
DOI:10.1038/nchem.1917
日期:2014.5
Multicomponent reactions allow for more bond-forming events per synthetic operation, enabling more step- and time-economical conversion of simple starting materials to complex and thus value-added targets. These processes invariably require that reactivity be relayed from intermediate to intermediate over several mechanistic steps until a termination event produces the final product. Here, we report a multicomponent process in which a novel 1,2,3-butatriene equivalent (TMSBO: TMSCH2Câ¡CCH2OH) engages chemospecifically as a two-carbon alkyne component in a metal-catalysed [5 + 2] cycloaddition with a vinylcyclopropane to produce an intermediate cycloadduct. Under the reaction conditions, this intermediate undergoes a remarkably rapid 1,4-Peterson elimination, producing a reactive four-carbon diene intermediate that is readily intercepted in either a metal-catalysed or thermal [4 + 2] cycloaddition. TMSBO thus serves as an yne-to-diene transmissive reagent coupling two powerful and convergent cycloadditionsâthe homologous DielsâAlder and DielsâAlder cycloadditionsâthrough a vinylogous Peterson elimination, and enabling flexible access to diverse polycycles. Cascade reactions allow step-economical generation of molecular complexity. Now, a butatriene equivalent, TMSCH2C â¡Â CCH2OH, is used to couple two powerful and convergent cycloadditions â the homologous DielsâAlder ([5 + 2]) and the DielsâAlder ([4 + 2]) reactions ââ through a vinylogous Peterson elimination, en route to a series of kinase inhibitors inspired by staurosporine.
多组分反应允许每个合成操作中形成更多的键,从而使简单的起始材料到复杂且具有高附加值的目标物的转化更加步骤和经济。这些过程通常需要在多个机理步骤中将反应性从一个中间体传递到另一个中间体,直到终止事件产生最终产物。这里,我们报告了一种多组分过程,其中一种新型的1,2,3-丁三烯等价物(TMSBO:TMSCH₂C≡CCH₂OH)作为一种双碳炔组分,在金属催化下与乙烯基环丙烷进行[5+2]环加成反应,生成一种中间体环加成物。在反应条件下,这种中间体经历了一种非常快速的1,4-Peterson消除,产生一种活性四碳二烯中间体,容易在金属催化或热[4+2]环加成反应中被截获。TMSBO因此作为从炔到二烯的传递剂,通过邻位Peterson消除连接两个强大的汇聚环加成反应——同源的Diels-Alder和Diels-Alder环加成反应——并实现了对多种多环结构的灵活访问。级联反应允许步骤经济的分子复杂性生成。现在,一种丁三烯等价物,TMSCH₂C≡CCH₂OH,被用来通过邻位Peterson消除连接两个强大的汇聚环加成反应——同源的Diels-Alder([5+2])和Diels-Alder([4+2])反应,通往一系列受staurosporine启发的激酶抑制剂。