Li Bao-Sheng, Wang Yuhuang, Jin Zhichao, Chi Yonggui Robin
Division of Chemistry & Biological Chemistry , School of Physical & Mathematical Sciences , Nanyang Technological University , Singapore , 637371 , Singapore . Email:
State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering , Ministry of Education , Guizhou University , Guiyang , 550025 , China.
Chem Sci. 2015 Oct 1;6(10):6008-6012. doi: 10.1039/c5sc01972a. Epub 2015 Jul 20.
The addition of an organic catalyst to the ketone moiety of a γ-mono-chloride substituted cyclobutenone destroys its stable, conjugated and nearly planar structure. The C-C bond in the resulting less stable anionic oxy-substituted non-planar intermediate is then activated. The breaking of one C-C single bond leads to a catalyst-bound intermediate that undergoes α-carbon selective reactions with azomethine imines to afford nitrogen-containing heterocyclic compounds with excellent diastereo- and enantio-selectivities. Our organocatalytic approach provides a new reaction pattern for C-C bond activation of cyclobutenones that is unavailable with transition metal catalysis. In addition, the present study with isothioureas as the organocatalysts expands the potential in using organocatalysts for C-C bond breaking and selective reactions.
向γ-单氯化取代的环丁烯酮的酮部分添加有机催化剂会破坏其稳定的、共轭的且近乎平面的结构。然后，所得稳定性较差的阴离子氧取代非平面中间体中的C-C键被活化。一个C-C单键的断裂会产生一种与催化剂结合的中间体，该中间体与偶氮甲碱亚胺发生α-碳选择性反应，从而得到具有优异非对映和对映选择性的含氮杂环化合物。我们的有机催化方法为环丁烯酮的C-C键活化提供了一种新的反应模式，这是过渡金属催化无法实现的。此外，本研究以异硫脲作为有机催化剂，拓展了使用有机催化剂进行C-C键断裂和选择性反应的潜力。
