Studies on regioselective addition of benzylic organometallics to α-oxoketene dithioacetals in our aromatic annelation protocol

Synthesis and crystal structure of 2-(1,3-dithietan-2-yl-idene)cyclo-hexane-1,3-dione

The title compound, C8H8O2S2, contains a cyclo-hexane-1,3-dione ring, which has a twist-boat conformation. The C2S2 ring is close to planar (r.m.s. deviation = 0.023 Å) and the dihedral angle between the mean planes of the cyclo-hexane and 1,3-dithietane rings is 9.1 (3)°. Short intra-molecular S⋯O contacts occur [2.719 (5) and 2.740 (5) Å]. In the crystal, the mol-ecules are linked by weak C-H⋯S hydrogen bonds and short [3.165 (5) Å] S⋯O contacts, forming (010) layers. The prevalence of these inter-actions is illustrated by an analysis of the three-dimensional Hirshfeld surface and by two-dimensional fingerprint plots.

Synthesis of 1-amino-2-aroyl/acetylnaphthalenes through a base mediated one pot inter and intramolecular C–C bond formation strategy

Base mediated synthesis of highly functionalized aroyl/acetylnaphthalenes by the reaction of 2-(1-cyano-2,2-bis(methylthio)vinyl)benzonitrile and aryl methyl ketone or acetone has been reported.

Recent developments of ketene dithioacetal chemistry

Ketene dithioacetals are versatile intermediates in organic synthesis. Extensive research, since the last decade, has given rise to new prospects in their chemistry. The objective of this review is twofold: first, to highlight the new prospects in the chemistry of functionalized ketene dithioacetals, and second, to provide an intrinsic link between ketene dithioacetal groups and a variety of other functional groups, which has brought out many new facts that will assist in future designs.

A Divergent Synthesis of Functionalized Unsaturated δ-Lactones from α-Alkenoyl-α-carboxyl Ketene Dithioacetals

A divergent synthesis of functionalized unsaturated delta-lactones 2, 3, 4, and 5 has been developed starting from the readily available alpha-alkenoyl-alpha-carboxyl ketene dithioacetals 1 in high to excellent yields under mild reaction conditions. Thus, 6-substituted 3-(1,3-dithiolan/dithian-2-ylidene)-3H-pyran-2(6H)-ones 2, obtained from a consecutive reduction with NaBH4 and acidic workup of 1 via a novel vinylogous Pummerer cyclization, can be further transformed into alpha-pyranones 3, 4, and 5 upon a sequential isomerization catalyzed by triethylamine (to give 3), followed by dethioacetalization (to give 4) or a formylation with Vilsmeier reagent (to give 5).

Regioselective Synthesis of 1-Aryl-3,4-substituted/annulated-5-(methylthio)pyrazoles and 1-Aryl-3-(methylthio)-4,5-substituted/annulated Pyrazoles

[reaction: see text] Highly efficient and regioselective synthesis of 1-aryl-3,4-substituted/annulated-5-(methylthio)pyrazoles and 1-aryl-3-(methylthio)-4,5-substituted/annulated pyrazoles has been reported via cyclocondensation of arylhydrazines with either alpha-oxoketene dithioacetals or beta-oxodithioesters.

[5 + 1] Annulation: A Synthetic Strategy for Highly Substituted Phenols and Cyclohexenones

A novel [5 + 1] annulation strategy is developed for the synthesis of highly substituted phenols and cyclohexenones from alpha-alkenoyl ketenedithioacetals and nitroalkanes.

[5C + 1N] Annulation: a novel synthetic strategy for functionalized 2,3-dihydro-4-pyridones

A novel and facile route to functionalized mono/bicyclic 2,3-dihydro-4-pyridones has been developed via formal [5C + 1N] annulation of readily available alpha-alkenoyl ketene-(S,S)-acetals with various aliphatic primary amines.