Iridium-Catalyzed Formal [4 + 1] Cycloaddition of Biphenylenes with Alkenes Initiated by C–C Bond Cleavage for the Synthesis of 9,9-Disubstituted Fluorenes
作者:Hideaki Takano、Kyalo Stephen Kanyiva、Takanori Shibata
DOI:10.1021/acs.orglett.6b00619
日期:2016.4.15
An Ir-catalyzed intermolecular reaction of biphenylenes as a C4 unit with various alkenes as a C1 unit gave 9,9-disubstituted fluorenes in moderate to high yields. Preliminary mechanistic studies revealed that this formal [4 + 1] cycloaddition probably proceeds via C–C bond cleavage, alkene insertion, β-hydrogen elimination, intramolecular alkene insertion, and then reductive elimination. An example
Ir催化的联苯作为C4单元与各种烯烃作为C1单元的分子间反应以中等至高收率得到9,9-二取代的芴。初步的机理研究表明,这种正式的[4 +1]环加成反应可能是通过C–C键断裂,烯烃插入,β-氢消除,分子内烯烃插入,然后是还原消除进行的。还公开了对映选择性反应的实例。