Synthesis and [3+2] cycloaddition reaction of 3-[(trimethylsilylmethylamino) (methylthio)-methylene]heterocyclic compounds

摘要

3-[(Trimethylsilylmethylamino)(methylthio)]methylene-2-coumaranone (4a) and 1-methyloxindole (4b), readily prepared by reactions of the corresponding bis(methylthio)methylene heterocyclic compounds (2a, b), with (trimethylsilylmethyl)amine (3), were found to be synthetic equivalents of heterocyclic alkylidene-azomethine yields. Reactions of 4a, b with reactive heterodipolarophiles such as aldehydes and ketones and reactive alkenes in the presence of cesium fluoride gave the 1,3-dipolar cycloadducts, 3-(2-oxazolidinylidene)-oxindole and -coumaran-2-one derivatives (8a-j, 9a-h), as well as pyrrolylidenecoumaran-2-one and oxindole derivatives (12-15, 17, 18), via the 1,3-elimination of (methylthio)trimethylsilane.