N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991, Moscow, Russian Federation.
Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 32 Vavilov st., 119991, Moscow, Russian Federation.
Angew Chem Int Ed Engl. 2016 Sep 26;55(40):12233-7. doi: 10.1002/anie.201603927. Epub 2016 Aug 30.
A new strategy for cascade assembly of substituted indenes and polycyclic lactones based on reactions of donor-acceptor cyclopropanes and styrylmalonates with aromatic aldehydes in the presence of GaCl3 has been developed. The use of GaCl3 makes it possible to principally change the direction of the reaction known in this series of substrates and to perform the process in a multicomponent version. Generation of formal 1,2-zwitterionic intermediates owing to complexation of dicarboxylate groups with GaCl3 is the driving force of the reactions discovered. This method makes it possible to assemble indenylmalonates or indano[1',2':2,3]indano[2,1-b]furan-2-ones in one synthetic stage from readily available starting compounds with high regio- and diastereoselectivity. A mechanism of the reactions has been suggested using the (18) O label in benzaldehyde.
一种基于供体-受体环丙烷和苯乙烯马来酸盐与芳香醛在 GaCl3 存在下的反应，用于取代茚和多环内酯的级联组装的新策略已经被开发出来。使用 GaCl3 可以从根本上改变这个系列底物中已知反应的方向，并以多组分的方式进行该过程。由于二羧酸酯基团与 GaCl3 的络合，形成了形式上的 1,2-两性离子中间体，这是发现的反应的驱动力。这种方法可以从易得的起始原料出发，在一个合成阶段高区域和立体选择性地组装茚基丙二酸酯或茚并[1',2':2,3]茚并[2,1-b]呋喃-2-酮。使用（18）O 标记的苯甲醛，提出了反应的机理。
