Loh Ying Kai, Melaimi Mohand, Munz Dominik, Bertrand Guy
UCSD-CNRS Joint Research Laboratory (UMI 3555), Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0358, United States.
Coordination Chemistry, Saarland University, Campus C4.1, 66123 Saarbrücken, Germany.
J Am Chem Soc. 2023 Feb 1;145(4):2064-2069. doi: 10.1021/jacs.2c12847. Epub 2023 Jan 17.
Carbenes, once considered laboratory curiosities, now serve as powerful tools in the chemical and material sciences. To date, all stable singlet carbenes are single-site ambiphiles. Here we describe the synthesis of a carbene which is a carbon-based ambiphile (both single-site dual-site). The key is to employ imino substituents derived from a cyclic (alkyl)(amino)carbene (CAAC), which imparts a 1,3-dipolar character to the carbene. Its ambiphilic nature is consistent with the ability to activate simple organic molecules in both 1,1- and 1,3-fashion. Furthermore, its 1,3-ambiphilicity facilitates an unprecedented reversible intramolecular dearomative [3 + 2] cycloaddition with a proximal arene substituent, giving the carbene the ability to "mask" itself as an air-stable cycloadduct. We perceive that the concept of ambiphilicity opens a new dimension for future carbene chemistry, expanding the repertoire of applications beyond that known for classical single-site ambiphilic carbenes.
卡宾曾被认为只是实验室里的新奇事物，如今却成为化学和材料科学中的强大工具。到目前为止，所有稳定的单线态卡宾都是单位点双亲体。在此，我们描述了一种卡宾的合成，它是一种基于碳的双亲体（单位点和双位点兼具）。关键在于使用源自环状（烷基）（氨基）卡宾（CAAC）的亚氨基取代基，这赋予了卡宾1,3 - 偶极特性。其双亲性质与以1,1 - 和1,3 - 方式活化简单有机分子的能力相一致。此外，其1,3 - 双亲性促进了与近端芳烃取代基发生前所未有的可逆分子内脱芳构化[3 + 2]环加成反应，使卡宾能够将自身“伪装”成一种空气稳定的环加成产物。我们认为，双亲性概念为未来的卡宾化学开辟了一个新的维度，拓展了应用范围，超越了经典单位点双亲性卡宾的已知应用。
