A copper‐catalyzedreductivecross‐coupling reaction of nonactivated alkyl tosylates and mesylates with alkyl and arylbromides was developed. It provides a practical method for efficient and cost‐effective construction of aryl–alkyl and alkyl–alkyl CC bonds with stereocontrol from readily available substrates. When used in an intramolecular fashion, the reaction enables convenient access to various
(C−O) bond in alkyl ethers could simplify chemical syntheses through the elaboration of these robust, readily available precursors. Here we report that dibromoboranes react with alkyl ethers in the presence of a nickel catalyst and zinc reductant to insert boron into the C−O bond. Subsequent reactivity can effect oxygen-to-nitrogen substitution or one-carbon homologation of cyclic ethers and more broadly
The Synthesis of 5-Substituted 2,3-Dihydrobenzofurans
作者:Ramon J. Alabaster、Ian F. Cottrell、Hugh Marley、Stanley H. B. Wright
DOI:10.1055/s-1988-27762
日期:——
The preparation of 2,3-dihydrobenzofurans 6 from 2-(2-bromophenoxy)ethyl chlorides 3 by reaction with magnesium in a development of the Parham cyclialkylation reaction is described. A high yielding procedure using phase-transfer catalysis has also been developed for the preparation of the intermediate chloroethyl ethers 3 from bromophenols 2. The 5-hydroxy derivative 15 may be obtained from 2,3 dihydrobenzofuran (6a) by reaction with electrophilic reagents followed by oxidation.
.alpha.-substituted benzenemethanamine derivatives and pharmaceutical use
申请人:Janssen Pharmaceutica N.V.
公开号:US05407961A1
公开(公告)日:1995-04-18
The present invention is concerned with antiretroviral (e.g. anti HIV-1) compounds having the formula ##STR1## Pharmaceutical compositions containing said compounds of formula (I-a) or (I-b), and processes of preparing said compounds and compositions.
Photochemical behaviour of 3.4-epoxyprecocene-I and related epoxychromans
作者:G. Ariamala、K.K. Balasubramanian
DOI:10.1016/s0040-4020(01)89238-3
日期:1989.1
A systematic study of photochemicalbehaviour of 3,4-epoxyprecocene-I and related epoxychromans was undertaken. Upon irradiation in acetone or cyclohexane, 3,4-epoxyprecocene-I was found to undergo photoisomerisation to the corresponding 3-chromanone . In contrast, the photochemicalbehaviour of analogous 3,4-dihydro-3,4-epoxy-2H-1-benzopyrans 3 was found to be dependent upon the nature of solvent