Xiangtai Meng

Convenient synthesis of substituted tetrahydrofuran via Lewis base catalyzed [3 + 2] domino reactions

A DABCO catalyzed domino reaction between 3-oxo-4-(2-oxoindolin-3-ylidene) butanoates and allenoates furnished 2,3,5-substituted tetrahydrofuran furan derivatives with oxindole moieties and two exocyclic double bonds in high yield. During this reaction, two carbon atoms and one oxygen atom of 3-oxo-4-(2-oxoindolin-3-ylidene) butanoates participated. Moreover, four isomers were synthesized and two of them can be isolated in this reaction.

Solvent-Controlled Switchable Domino Reactions of MBH Carbonate: Synthesis of Benzothiophene Fused α-Pyran, 2,3-Dihydrooxepine, and Oxatricyclodecene Derivatives

Solvent-controlled switchable domino reactions between 2-alkylidenebenzothiophene-3(2H)-ones and Morita-Baylis-Hillamn (MBH) carbonate were developed. All domino reactions exhibited excellent regioselectivity, producing a broad spectrum of benzothiophene-fused α-pyran, 2,3-dihydrooxepine, and oxatricyclodecene derivatives. Furthermore, [4 + 2], [4 + 3], and related domino reactions from identical substrates can be controlled.

Synthesis of Dibenzothiophene and 1,4-Dihydrodibenzothiophene Derivatives via Allylic Phosphonium Salt Initiated Domino Reactions

Two efficient synthetic protocols were developed for the synthesis of dibenzothiophene and 1,4-dihydrodibenzothiophene using thioaurones and allylic phosphonium salt. Mild reaction conditions, a one-pot procedure, and easily accessible starting materials make these protocols powerful tools for the synthesis of these compounds, which are often used in material and pharmaceutical sciences.

Phosphine-Catalyzed Domino Reaction of Thioaurones and Allenoate: Synthesis of Benzothiophene-Fused Dioxabicyclo[3.3.1]nonane Derivatives

The reaction of thioaurone derivatives with allenoate catalyzed by tris(4-methoxyphenyl)phosphane (P(4-MeOC6H4)3) resulted in a domino annulation reaction to produce a benzothiophene-fused bridged bicyclic ring, with 40-91% yields. The advantages of the methodology include diastereoselective formation of a bridged bicyclic ring in a single step, very mild reaction conditions, and success resulting from a broad functional group. The proposed mechanism was tested and supported by DFT calculations.