Reactions of a Dilithiomethane with CO and N<sub>2</sub>O: An Avenue to an Anionic Ketene and a Hexafunctionalized Benzene
Maotong Xu, Tongtong Wang, Zheng‐Wang Qu, Stefan Grimme, Douglas W. Stephan
Abstract
Abstract Synthesis of value‐added products from simple C1 feedstocks is an attractive alternative avenue to traditional fossil fuels. Hexa‐substituted benzene derivatives are highly useful molecules but are often challenging to prepare. Herein, we report that the lithium complex [(Ph 2 P(S)) 2 CLi 2 (THF)] 2 1 reacts with CO lead to C−C bond formation and migration of a Ph 2 P( S )‐fragment affording 2 . Subsequent reaction with N 2 O results in oxidative cleavage of a P−C bond affording [Ph 2 P(S)OLi(THF) 2 ] 2 4 and the anionic ketene‐derivative Ph 2 P(S)CCOLi(THF) 2 5 . Heating 5 prompts cyclotrimerization giving the hexa‐substituted benzene derivative [Ph 2 P(S)CCOLi(THF) 2 ] 3 6 regioselectively. This transition metal‐free protocol to a hexa‐substituted benzene is viable on a gram scale and permits the incorporation of 13 C labels. The mechanisms of these reactions are detailed via extensive DFT computations.