Institute for Advanced Study, Chengdu University, Chengdu 610106, China.
Org Biomol Chem. 2019 May 29;17(21):5294-5304. doi: 10.1039/c9ob00775j.
An efficient Ph2PMe-catalyzed dearomative (3 + 2) annulation of 2-nitrobenzofurans, 2-nitrobenzothiophenes, and 3-nitrobenzothiophenes with allenoates has been developed. With the developed protocol, a series of structurally important cyclopenta[b]benzofurans and cyclopenta[b]benzothiophenes were obtained in good to excellent yields (up to 98%) under mild conditions. In addition, preparative-scale experiments and transformations were conducted to exemplify the synthetic utility. The asymmetric version of this dearomative (3 + 2) annulation reaction was tentatively investigated by using chiral phosphine catalysts.
一种高效的 Ph2PMe 催化的 2-硝基苯并呋喃、2-硝基苯并噻吩和 3-硝基苯并噻吩与丙二烯酸酯的去芳构化（3 + 2）环加成反应已经被开发出来。在开发的方案中，在温和条件下，一系列结构重要的环戊并[b]苯并呋喃和环戊并[b]苯并噻吩以良好至优异的收率（高达 98%）得到。此外，进行了制备规模的实验和转化以例证合成的实用性。通过使用手性膦催化剂，初步研究了这种去芳构化（3 + 2）环加成反应的不对称版本。
