Visible-Light-Mediated Synthesis of Thio-Functionalized Pyrroles

Abstract

An inimitable illustration of the green-light-induced synthesis of thio-functionalized pyrroles has been established using β-ketodinitriles and thiophenols as the reacting partners and eosin Y as the photocatalyst. Large-scale synthesis and some useful synthetic modifications of the thio-functionalized pyrroles are also demonstrated.

Organo-photocatalytic Synthesis of Functionalized Pyrroles from 2H-Azirines and α-Substituted Nitroalkenes

“…2 Recent progress in the field of visible-light-mediated heterocycle synthesis 3 has inspired the discovery of several elegant protocols for the synthesis of pyrrole derivatives, including organometallic photocatalyst-mediated protocols such as the Hantzsch synthesis of 2,5-diaryl-substituted pyrroles, 4 the Paal–Knorr type synthesis of 1,3,4-trisubstituted pyrroles via condensation of aryl azides with aldehydes, 5 and the synthesis of the 2,3-fused pyrrole motif via coupling of naphthols and naphthoquinones with 2 H -azirines. 6 Moreover, strategies employing organic dyes as photocatalysts for the synthesis of thio-functionalized pyrroles 7 and tetra-/trisubstituted pyrroles through formal [3+2] cycloaddition of 2 H -azirines with alkynes 8 or nitroalkenes 9 have been reported. Our group recently employed pyrylium salts in a dual role as a photosensitizer and dipolarophile in the dipolar cycloaddition with 2 H -azirines for accessing chalcone-bearing tetrasubstituted pyrroles.…”

“…2 Recent progress in the field of visible-light-mediated heterocycle synthesis has inspired the discovery of several elegant protocols for the synthesis of pyrrole derivatives, including organometallic photocatalyst-mediated protocols such as the Hantzsch synthesis of 2,5-diaryl-substituted pyrroles, 4 the Paal-Knorr type synthesis of 1,3,4-trisubstituted pyrroles via condensation of aryl azides with aldehydes, 5 and the synthesis of the 2,3-fused pyrrole motif via coupling of naphthols and naphthoquinones with 2H-azirines. 6 Moreover, strategies employing organic dyes as photocatalysts for the synthesis of thio-functionalized pyrroles 7 and tetra-/trisub-…”

Molecular diversity of the base-promoted reaction of phenacylmalononitriles with dialkyl but-2-ynedioates

“…In many practical cases, phenacylmalononitriles could be conveniently generated in situ by directly using a mixture of phenacyl bromide and malononitrile in the reaction system [17][18][19][20][21][22]. As a consequence, the unique features of phenacylmalononitriles make them good candidates for the efficient construction of diverse carbocyclic and heterocyclic compounds [23][24][25][26][27][28][29][30]. For example, Han and co-workers successfully developed a tetrabutylammonium fluoride-catalyzed cycloaddition of phenacylmalononitriles and nitroolefins for the diastereoselective synthesis of multifunctionalized cyclopent-2-ene-1-carboxamides [31] (reaction 1 in Scheme 1).…”

Selective synthesis of multifunctionalized cyclopent-3-ene-1-carboxamides and 2-oxabicyclo[2.2.1]heptane derivatives

“…9 In recent years, many elegant synthetic protocols for diverse carbo- and heterocyclic compounds by using phenacylmalononitriles as key substrates have been successfully developed. 10,11 Inspired by these novel reactions and in continuation of our aim to develop domino reactions for functionalized heterocyclic compounds, 12,13 here we wish to report the selective synthesis of cyclopent-1-ene-1,2-dicarboxylates and 2-oxabicyclo[2.2.1]heptane in good yields and with high diastereoselectivity by base promoted reactions of phenacylmalononitriles with o -hydroxychalcones and their o -enolates.…”