Functionalisation in position 3 of 3,5-dichloro-2H-1,4-oxazin-2-ones
摘要:
Electrophilic catalysis is shown to give selective substitution of the imidoyl chloride group in 3,5-dichloro-2H-1,4-oxazin-2-ones, avoiding competitive reactions of the nucleophile with the lactone function. With other nucleophiles (SCN-, CH2N2) cyclisations involving the azadiene- or the imine function take place. Cycloaddition of the obtained oxazinones to acetylenic compounds provides polyfunctionalized pyridines.
Functionalized o-bis(chloromethyl)pyridines as precursors for pyridine o-quinodimethane analogues and their [4+2] cycloadducts
作者:Peter R. Carly、Frans Compernolle、Georges J. Hoornaert
DOI:10.1016/0040-4039(95)00169-d
日期:1995.3
From oxazinones 4, precursors for pyridine o-quinodimethaneanalogues are made accessible via cycloaddition with 1,4-dichloro-2-butyne and propargyl chloride. Subsequent 1,4-elimination of the polyfunctional o-bis(chloromethyl)-pyridines affords both 2,3- and 3,4-dimethylene compounds, which are trapped in situ with various dienophiles.