The oxyindation of carbonyl-ene-yne compounds with indium trihalides proceeded efficiently to give di-, tri-, and tetrasubstituted 2-pyrones bearing a carbon-indium bond. The metalated 2-pyrone and a zwitterion intermediate were identified by X-ray crystallographic analysis. The application of organoindium compounds to oxidation or cross-coupling provided easy access to various multifunctionalized
An efficient synthesis of tetrahydro-1,3-oxazepines was developed involving the regioselective intramolecular amination of cyclopropylmethyl cation. The cation was generated by the abstraction of one imidate group in bis-imidate bearing a carbocation-stabilizing substituent. Using 1,1,2,3-tetrasubstituted cyclopropane substrates, highly diastereoselective intramolecular amination to trans-tetrahydro-1,3-oxazepines was achieved. The resulting tetrahydro-1,3-oxazepines were transformed to the homoallylamine derivatives in high yields.
Three-Component Reaction of Dimethyl Malonate with α,β-Acetylenic Aldehydes and Amines. Synthesis of Push–Pull Buta-1,3-dienes
作者:S. A. Sokov、I. S. Odin、S. S. Zlotskii、A. A. Golovanov
DOI:10.1134/s1070428020100140
日期:2020.10
Three-component reaction of dimethyl malonate with alpha,beta-acetylenic aldehydes and cyclic secondary amines (pyrrolidine, piperidine, morpholine, and piperazine) under mild conditions afforded dimethyl 2-(3-aminoprop-2-en-1-ylidene)malonates in 50-91% yields. The products were formed preferentially as E isomers, and the described reaction provides a convenient method for the synthesis of push-pull buta-1,3-dienes that are interesting as fluorescent, solvatochromic, and nonlinear optical materials and starting compounds in the synthesis of carbo- and heterocycles. A plausible reaction mechanism involves Knoevenage condensation of dimethyl malonate with alpha,beta-acetylenic aldehyde to give dimethyl 2-(prop-2-yn-1-ylidene)malonate and subsequent nucleophilic addition of cyclic amine to the latter.
Castaner; Pascual, Anales de la Real Sociedad Espanola de Fisica y Quimica, 1957, vol. <B> 53, p. 651,654