Annelation reactions of 4-alkynylcyclobutenones. Formation of methylenebenzofurans
作者:Simon L. Xu、Meng Taing、Harold W. Moore
DOI:10.1021/jo00021a026
日期:1991.10
Thermolysis of a number of 4-alkynyl-4-(propargyloxy)cyclobutenones is reported. These studies show a remarkable rearrangement to methylenebenzofurans accompanied by remote alkene formation. The mechanism and scope of the reactions are discussed.
Synthesis of [3-D3]-, [3-13C]-, and [1,2-13C2]Propynes and Their Use for the Synthesis of [5-D3-Methyl]-, [5-13C-Methyl]-, and [5,6-13C2-2,5-Cyclohexadienyl]ubiquinones 3
Three selectively labeled propynes were prepared either with deuterium or carbon-13 at position 3 and doubly labeled with carbon-13 at positions 1 and 2 by an alkylation reaction from the corresponding labeled or unlabeled monolithio acetylides and dimethylsulfates. Their lithiation with nBuLi gave the corresponding propynyllithium derivatives which reacted with dimethyl squarate to afford the corresponding