Less highly substituted silyl enol ethers are regiospecifically prepared in high yield, around room temperature under kinetic conditions, from unsymmetrical cyclic ketones and magnesium bis(diisopropylamide) [(DA)2Mg] in THF/heptane. This high regioselectivity is markedly higher than these reported for bromomagnesium diisopropylamide (DAMgBr); it is also similar to this of LDA/DME at −78°C, but (DA)2Mg
A convenient method for the preparation of α-vinylfurans by phosphine-initiated reactions of various substituted enynes bearing a carbonyl group with aldehydes
at the ene end in the presence of various aldehydes, in moderate to high yields. The reaction may consist of 1,6-addition of phosphine to the enynes, ring closure, and Wittig reaction between the ylid resulting from cyclization and an aldehyde. Thus, various aldehydes were able to be used in the reaction. The reaction was influenced greatly by the substituents at the acetylene position (R1) and the α-position
Oxidation reactions using polymer-supported 2-benzenesulfonyl-3-(4-nitrophenyl)oxaziridine
作者:Woen Susanto、Yulin Lam
DOI:10.1016/j.tet.2011.08.058
日期:2011.10
A thermally stable polymer-supported oxidant has been developed. Polymer-supported 2-benzenesulfonyl-3-(4-nitrophenyl)oxaziridine was applied to microwave-assisted reactions that occurred at high temperatures and was shown to oxidize alkenes, silyl enol ethers, and pyridines to the corresponding epoxides and pyridine N-oxides in excellent to good yields and with much shorter reaction times. It also
A Convenient Synthesis of Episulfides and Their Conversion into Alkenes
作者:Piotr Dybowski、Aleksandra Skowrońska
DOI:10.1055/s-1997-1329
日期:1997.10
A convenient and stereoselective synthesis of episulfides based on the reaction of readily available S-(β-oxoalkyl) thiophosphate with sodium borohydride and their conversion into alkenes is described.
作者:Oleg V. Fedorov、Mikhail D. Kosobokov、Vitalij V. Levin、Marina I. Struchkova、Alexander D. Dilman
DOI:10.1021/acs.joc.5b00904
日期:2015.6.5
involves silylation, difluorocarbene addition using Me3SiCF2Br activated by a bromide ion, and halogenation of intermediate cyclopropanes with N-bromo- or N-iodosuccinimide. The whole process is performed without isolation of intermediates. The resulting α,α-difluoro-β-halo-substituted ketones can be readily converted into fluorine containing pyrazole derivatives and oxetanes.