A Highly Active Ytterbium(III) Methide Complex for Truly Catalytic Friedel-Crafts Acylation Reactions
作者:Anthony G. Barrett、Nathalie Bouloc、D. Christopher Braddock、David Chadwick、David A. Henderson
DOI:10.1055/s-2002-34231
日期:——
The Friedel-Crafts acylation of anisole with acetic anhydride using ytterbium(III) tri[tris(nonafluorobutanesulfonyl)methide] was studied with respect to catalyst loading. A strong inhibitory effect due to the product became apparent from doping experiments and from examination of the kinetic data. This understanding allowed catalyst loadings to be reduced to as little as 0.1 mol% for effective acylation
The reactions of tris(2-thienyl)stibanes with various acyl chlorides, using a catalytic amount of iron(III) chloride, afforded 2-acylthiophenes. Iron(III) chloride is presumed to act as a Lewis acid, and the ipso substituent of each 2-thienyl group of tris(2-thienyl)stibane is replaced with an acyl group. The reaction is highly atom-efficient in that all three thiophene rings of tris(2-thienyl)stibane take part in the reaction. The reaction procedure is so simple that it can also be carried out under solvent-free and aerobic conditions.
Hydantoins as Anticonvulsants. I. 5-R-5-(2-Thienyl)-hydantoins<sup>1</sup>
作者:James J. Spurlock
DOI:10.1021/ja01101a031
日期:1953.3
Highly Selective 5-Substitution of 3-Methylthiophene via Directed Lithiation
作者:Keith Smith、Mark Lewis Barratt
DOI:10.1021/jo062024f
日期:2007.2.1
Lithiation of 3-methylthiophene with lithium 2,2,6,6-tetra-methylpiperidide (LiTMP) is highly selective at the 5-position, and reaction with a range of electrophiles gives high yields of the corresponding 2,4-disubstituted thiophenes, even when unhindered electrophiles are used.