Envirocat (K10-MX)–Catalyzed Regioselective Transformation of Alkenes into Iodohydrins and <font>β</font>-Iodo Ethers and Further Conversion of Iodohydrins to Epoxides Using Al<sub>2</sub>O<sub>3</sub>-Na<sub>2</sub>CO<sub>3</sub> Under MWI
作者:Shallu、M. L. Sharma、Jasvinder Singh
DOI:10.1080/00397911.2010.539755
日期:2012.5.1
converted to extremely efficient and environmentally friendly catalyst K10-MX for the preparation of iodohydrins and β-iodo ethers from alkenes (terminal as well as internal) using microwave irradiation. This method was further extended for the conversion of alkenes to epoxides via iodohydrin intermediate in a one-pot reaction system. GRAPHICAL ABSTRACT
Syntheses of tetrahydropyrans by PPh3/CBr4 induced cyclization of acetals: Application to a synthesis of rose oxide
作者:A. Wagner、M.-P. Heitz、C. Mioskowski
DOI:10.1016/s0040-4039(00)99627-8
日期:1989.1
Substituted tetrahydropyrans are prepared in good yields by PPh3/CBr4 induced cyclization of acetals. The utility of this new procedure is illustrated by the synthesis of cis-2-(2-methyl-1 propenyl)- 4 methyltetrahydropyran (roseoxide).
A facile route to iodohydrins and epoxides by oxidation of olefin-iodine complexes with pyridinium dichromate
作者:Roberto Antonioletti、Maurizio D'Auria、Antonella De Mico、Giovanni Piancatelli、Arrigo Scettri
DOI:10.1016/s0040-4020(01)88685-3
日期:1983.1
Trisubstituted olefins, activated with I2, are changed into iodohydrins and epoxides by pyridinium dichromate. The conversion shows to proceed in regiospecific and stereospecific manner. Moreover some naturally occurring polyenes, submitted to similar treatment, afford selectively only terminal iodohydrins. These latter are converted into the corresponding epoxides through a new and convenient alumina
Regioselective Carbon-Carbon Bond Formation in Titanium Mediated Reaction of Ethylmagnesium Bromide with Allylic Alcohols and Allylic Ethers
作者:Oleg G. Kulinkovich、Oleg L. Epstein、Vladimir E. Isakov、Ekaterina A. Khmel'nitskaya
DOI:10.1055/s-2001-9707
日期:——
In the presence of Ti(Oi-Pr)4 reaction of EtMgBr with allylic alcohols and allylicethers affords the products of formal SN2′ substitution of hydroxy or alkoxy groups with ethyl groups in moderate to good yields and excellent regioselectivity. The mechanism of the reaction includes the formation of titanacyclopropanes as the key organometallic intermediates. Promoting action of EtMgBr on the process
Triphenylphosphine hydrobromide is a convenient and highly effective catalyst for tetrahydropyranylation of tertiary alcohols with dihydropyran in dichloromethane at ambient temperature.