1408058-85-4Relevant articles and documents
Fine-Tunable 3,4-dihydroquinazol-2-ylidene carbenes: Synthesis, rhodium(I) complexes, and reactivity
Zhang, Jun,Qin, Xinke,Fu, Jun,Wang, Xiao,Su, Xiaolong,Hu, Fangle,Jiao, Jiajun,Shi, Min
, p. 8275 - 8282 (2013/02/22)
The design and synthesis of various new six-membered cyclic formamidinium salts with a 3,4-dihydroquinazoline core have been reported in this paper. Our synthetic strategy allows access to a kind of tailor-made 3,4- dihydroquinazolinium salts bearing different substituent combinations. A series of novel 3,4-dihydroquinazolin-2-ylidene-based rhodium(I) complexes were prepared by the reaction of [Rh(cod)Cl]2 with the free carbene obtained in situ from the deprotonation of the corresponding 3,4-dihydroquinazolinium salts with KN(SiMe3)2. The NHCs prepared in situ can also react with S8 or CS2 to afford the corresponding thiones or NHC-CS2 adducts, respectively. The rhodium(I) complexes were transformed to the corresponding dicarbonyl complexes, and the ν(CO) values of the corresponding dicarbonyl Rh complexes indicate the 3,4-dihydroquinazol-2-ylidenes are stronger electron donors than normal five-membered NHCs. The Rh complexes are highly active in the arylation of carbonyl compounds, and the 3,4-dihydroquinazolin-2-ylidenes prepared in situ upon deprotonation are powerful in palladium-catalyzed Suzuki cross-coupling reactions at room temperature with a ppm scale catalyst loading with TONs of up to 425 000.
