Synthesis and [3+2]Cycloaddition Reaction of 3-[(Trimethylsilylmethylamino)(methylthio)]-methylene-2-coumaranone and -1-methyyloxindole: Synthetic Equivalent of Heterocyclic Alkylideneazomethine Ylide as a Novel 1,3-Dipolar Reagent
作者:Yoshinori Tominaga、Satoshi Takada、Shinya Kohra
DOI:10.3987/com-93-s(b)4
日期:——
3-[(Trimethylsilylmethylamino)(methylthio)] methylene-2-coumaranone (4a) and -1-methyloxindole (4b), readily prepared by reaction of the corresponding bis(methylthio)methyleneheterocyclic compounds (2a, b) with trimethylsilylmethylamine (3), were found to be synthetic equivalent of heterocyclic alkylideneazomethine ylides. Reaction of 4a, b with reactive heterodipolarophiles such as aldehydes and ketones in the presence of cesium fluoride gave 1,3-dipolar cycloadducts, 3-(2-oxazolidinylidene)-2-coumaranone and-1-methyloxindole derivatives (8a-j, 9a-h), via the 1,3-elimination of (methylthio)trimethylsilane.