Domino Synthesis of Tetrasubstituted Thiophenes from 1,3-Enynes with Mercaptoacetaldehyde

Abstract

Domino synthesis of tetrasubstituted thiophenes is described from 1,3-enynes and mercaptoacetaldehyde using DABCO at room temperature via a Michael addition, 5-exo-dig carboannulation, and oxidation sequence under air. The broad substrate scope and mild reaction conditions are significant practical features.

Organocatalytic Three‐Component, One‐Pot Reaction of Highly Substituted Tetrahydropyrano[2, 3‐c]pyrazoles

“…Furthermore, the use of 1‐nitro‐1,3‐enynes in sequential catalytic reactions that combine metal catalysis and organocatalysis to generate pyrano‐annulated pyrazoles and tetrahydrofuranyl derivatives was reported by Enders and Krause/Alexakis, respectively. The use of ( E )‐2‐nitro‐1,3‐enynes for the synthesis of highly substituted pyrroles and thiophenes has been reported by Punniyamurthy. The pyrano‐annulated molecular architectures can be readily assembled by using ( E )‐2‐nitro‐1,3‐enynes in organocatalytic tandem reactions via in situ formation of an allene (Scheme , eqs a and b) .…”

1,4‐Dithiane‐2,5‐diol: An Attractive Platform for the Synthesis of Sulfur‐Containing Functionalized Heterocycles

“…[51] The broad substrate scope and mild reaction conditions are significant and practical features, but the main advantages of this sequence are the direct introduction of aldehyde and NO 2 /COPh/CO 2 Et functionalities on the thiophene ring under metal-free and mild conditions. [51] The broad substrate scope and mild reaction conditions are significant and practical features, but the main advantages of this sequence are the direct introduction of aldehyde and NO 2 /COPh/CO 2 Et functionalities on the thiophene ring under metal-free and mild conditions.…”

“…More recently (Scheme 23), the same group described the preparation of tetrasubstituted thiophenes 68 from 1,3-enynes 67 and 1 in the presence of DABCO at room temperature, in a domino reaction sequence involving Michael addition, 5-exodig carboannulation and oxidation under air. [51] The broad substrate scope and mild reaction conditions are significant and practical features, but the main advantages of this sequence are the direct introduction of aldehyde and NO 2 /COPh/CO 2 Et functionalities on the thiophene ring under metal-free and mild conditions. Scheme 23.…”

Reaction between Chalcones, 1,3-Dicarbonyl Compounds, and Elemental Sulfur: A One-Pot Three-Component Synthesis of Substituted Thiophenes

“…carbaldehydes through a reaction between 1,3-enynes and 1,4-dithiane-2,5-diol in the presence of DABCO (Scheme 1, equation III). 10 Very recently, Deng et al have reported a one-pot synthesis of 2,3,5-trisubstituted thiophenes through the three-component assembly of arylacetaldehydes, 1,3-dicarbonyl compounds, and elemental sulfur (Scheme 1, equation IV). However, the α,β-unsaturated aldehyde, acrolein, did not afford the corresponding thiophene upon treatment with 2,4-pentanedione under the standard conditions (Scheme 1, equation V).…”