General Reactivity of 2-Lithiobenzothiazole to Various Electrophiles and the Use as a Formyl Anion Equivalent in the Synthesis of α-Hydroxy Carbonyl Compounds
demonstrated by its reaction with phenacyl halides and 5-chloro-2-pentanone leading to the formation of benzothiazolyl-substituted small-ring ethers. In order to demonstrate the value of 2-lithiobenzothiazole as a masked formyl anion, 2-(α-hydroxyalkyl)benzothiazoles were transformed into α-hydroxy carbonyl compounds in three reaction steps without masking the α-hydroxygroups. Quaternization of various
Metal-free deprotonative functionalization of heteroaromatic compounds was achieved using an organic superbase catalyst; an organosilicon additive such as trimethylsilylpropyne was employed for activating the catalytic cycle of 1,2-addition to carbonyl compounds.
In Situ Generation and Trapping of Aryllithium and Arylpotassium Species by Halogen, Sulfur, and Carbon Electrophiles
作者:Ilya Popov、Hien-Quang Do、Olafs Daugulis
DOI:10.1021/jo9015369
日期:2009.11.6
A general method has been developed for in situ trapping of arylmetal intermediates by halogen, sulfur, ketone, and aldehyde electrophiles affording the functionalization of the most acidic position in arene Pentafluorobenzene, benzothiazole,and benzoxazole can be functionalized by using K3PO4 base. For less acidic arenes, tBuOLi base is required. Arenes with DMSO pK(a) values of 35 or less are reactive.
Ramos, M. Teresa; Avendano, Carmen; Elguero, Jose, Bulletin des Societes Chimiques Belges, 1989, vol. 98, # 7, p. 497 - 502
作者:Ramos, M. Teresa、Avendano, Carmen、Elguero, Jose、Jimeno, M. Luisa