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
Direct C2-Alkylation of Azoles with Alcohols and Ethers through Dehydrogenative Cross-Coupling under Metal-Free Conditions
作者:Tao He、Lin Yu、Lei Zhang、Lei Wang、Min Wang
DOI:10.1021/ol201779n
日期:2011.10.7
metal-free novel, simple, and highly efficient method for the direct C2-alkylation of azoles with alcohols and ethers has been developed on the basis of an oxidative C–H activation process. The dehydrogenative C–C cross-coupling reactions of α-position sp3 C–H in alcohols and ethers with the 2-position sp2 C–H in azoles proceeded smoothly in the presence of tert-butyl hydroperoxide (TBHP) under neat reaction
Alcohols were found to be arylated directly at their α‐C−H bond with arylhalides in the presence of a base and a substoichiometric amount of t ‐BuOOt ‐Bu through a homolytic aromatic substitution mechanism.
An electrophotochemical ring-opening bromination of unstrained tert-cycloalkanols has been developed. This electrophotochemical method enables the oxidative transformation of cycloalkanols with 5- to 7-membered rings into synthetically useful ω-bromoketones without the use of chemical oxidants or transition-metal catalysts. Alkoxy radical species would be key intermediates in the present transformation
catalysis and hydrogen atom transfer to achieve the alkylation of 2H-benzothiazoles with alcohols, ethers, lactams, amides and alkane, which features broad substrate scope and excellent functional group compatibility. Notably, alcohols can be used not only as hydroxyalkylating reagents, but also as dehydroxyalkylating reagents in this regulable alkylation protocol. The previous elusive self-photocatalytic