Mischmetall, an alloy of the light lanthanides, has been used in a variety of organicreactions, either as a coreductant in samarium(II)-mediated reactions (Barbier and Grignard-type reactions, pinacoliccouplingreactions) or as the promoter of Reformatsky-type reactions. It has been also employed as the starting material for easy syntheses of lanthanide trihalides, the reactivity of which has been
Neodymium(III)-Mediated Reformatsky-Type Reactions of α-Halo Ketones with Carbonyl Compounds
作者:Stefan F. Kirsch、Clémence Liébert
DOI:10.1002/ejoc.200700240
日期:2007.8
In a neodymium(III) iodide induced process, α-bromo ketones 1 and aldehydes 2 are effectively converted into aldol products 3. This Reformatsky-type reaction proceeds through the formation of a neodymium enolate at room temperature in CH2Cl2. The analogous reaction in the presence of NdBr3/NaI at 50 °C in THF favors the formation of corresponding aldol–Tishchenko products 5 in good yields. Studies
A ring expansion method for the preparation of 2,3-dihydro-1,4-benzothiazines from 2-aryl-2,3-dihydrobenzothiazoles
作者:Sabir H. Mashraqui、Richard M. Kellogg
DOI:10.1016/s0040-4039(00)99070-1
日期:1985.1
In the presence of KF in dimethylformamide (DMF) 2-aryl-2,3-dihydrobenzothiazoles react with α-haloketones to provide in good yield 2,3-dihydro-2,3-disubstituted-1,4- benzothiazines.
Development of N,N-bis(perfluoroalkanesulfonyl)squaramides as new strong Brønsted acids and their application to organic reactions
作者:Cheol Hong Cheon、Hisashi Yamamoto
DOI:10.1016/j.tet.2010.03.120
日期:2010.6
l groups have been developed and applied to several organic reactions. These squaramides are bench-stable and exhibit much higher reactivities in several organic reactions than squaric acid itself. N,N-Bis(trifluoromethanesulfonyl)squaramide 2a was applied to the Mukaiyama aldol reaction and Mukaiyama Michael reaction. Mechanistic studies revealed that the Brønsted acid might be the predominant catalyst