Triphenylphosphine promoted addition of dimethyl acetylenedicarboxylate to 1,2-benzoquinones: facile synthesis of novel γ-spirolactones

Triphenylphosphine promoted addition of acetylenic esters to benzofuran-2,3-dione: One-pot synthesis of novel γ-spirolactones

“…[16][17][18] We have also demonstrated that the activated carbonyl of phenyl glyoxalate and isatin derivatives can take part in such reactions successfully, thus constituting a ready synthesis of heterocyclic compounds. [19][20] We now wish to report a simple one-pot three-component reaction between dialkyl acetylenedicarboxylates, Ph3P, and benzofuran-2,3-dione derivatives leading to methyl 4'-methoxy-spiro[benzofuran-3,2'-furan]-2,5'-dione-3'-carboxylate derivatives as γ-spirolactone systems (Scheme 2 and Table 1 …”

Synthesis of Some Novel γ-Spiroiminolactones from Reaction of Cyclohexyl Isocyanide and Dialkyl Acetylene Dicarboxylates with 1-Benzylisatin and Tryptanthrine

“…[7][8][9][10] The initially formed zwitterionic intermediate has been shown to undergo further reaction with DMAD and isocyanide in different molar proportions, leading to a variety of complex heterocyclic compounds and these reactions have been the subject of detailed investigation by a number of research groups. [11][12][13] In this experiment, we observed that a mixture of 1-benzylisatin or tryptantrin and dialkyl acetylenedicarboxylates at 80 C in benzene or toluene when treated with cyclohexyl isocyanide afforded the products that was characterized as 3 and 4 (Sch. 1).…”

Reaction Between Triphenylphosphine and Acetylenic Esters or Acetylenic Ketones in the Presence of Mercaptoesters

“…However, there are also many reports on the reaction between triphenylphosphine and acetylenic esters in the presence of an electrophile in which triphenylphosphine acted as catalyst. [4][5][6][7] In fact, in these reactions, nucleophilic triphenylphosphine connected together the two electrophilic substrates. In continuation of our previous work on the reaction between trivalent phosphorus nucleophiles with acetylenic esters in the presence of organic acidic compounds, [8][9][10][11] here we report the results of our studies on the reaction between triphenylphosphine and electron-deficient acetylenic ketones or esters in the presence of S-H acidic compounds such as mercaptothioglycolate or methyl 3-mercaptopropanoate.…”