Conversion of (Z)-1,4-dihydroxyalk-2-enes into 2,5-dihydrofurans and of alkane-1,4-diols into tetrahydrofurans via acid-catalysed cyclisation of the monoisoureas formed by their copper(i)-mediated reactions with dicyclohexylcarbodiimideElectronic supplementary information (ESI) available. Experimental data for compounds 14a–f, 15a–f, 7a–f, 22a–g, 21a–e and 2b–e: See http://www.rsc.org/suppdata/p1/b2/b203389p/
Ni(0)-Catalyzed 1,4-Selective Diboration of Conjugated Dienes
作者:Robert J. Ely、James P. Morken
DOI:10.1021/ol101797f
日期:2010.10.1
stereoselective 1,4-diboration of conjugated dienes with B2(pin)2 was accomplished with Ni(cod)2 and PCy3 as the catalyst. This reaction broadens the substrate scope of current methods for catalytic diene diboration by including internal and sterically hindered dienes, and it proceeds efficiently at low catalyst loadings. The intermediate allylboronate was oxidized to the stereodefined allylic 1,4-diol.
Synthesis of Cyclic N-Tosyliminocarbonates by Lewis Acid Catalyzed Allylic Substitution of Trichloroacetimidates
作者:Liene Grigorjeva、Aigars Jirgensons
DOI:10.1002/ejoc.201200378
日期:2012.9
Allylic trichloroacetimidates bearing a δ-N-tosylcarbamoyloxy group were prepared in two steps from the corresponding diols, and their Bronsted and Lewisacidcatalyzed cyclization reactions were investigated. It was found that N-tosylcarbamates derived from secondary and tertiary alcohols bearing alkyl substituents undergo a chemoselective allylic alkylation to give N-tosyliminocarbonates in good
A Redox-Relay Heck Approach to Substituted Tetrahydrofurans
作者:Tom J. M. Byrne、Megan E. Mylrea、James D. Cuthbertson
DOI:10.1021/acs.orglett.3c00769
日期:——
An operationally simple and efficient strategy for the synthesis of substituted tetrahydrofurans from readily available cis-butene-1,4-diol is described. A redox-relay Heck reaction is used to rapidly access cyclichemiacetals that can be directly reduced to afford the corresponding 3-aryl tetrahydrofuran. Furthermore, the hemiacetals can also serve as precursors to a range of disubstituted tetrahydrofurans