Regio- and Stereoselective Intermolecular 1,2-Difunctionalization of Terminal Alkynes: An Approach to Access (Z)-β-Amidovinylsulfones

Abstract

We have developed the first I2/base-catalyzed regio- and stereoselective intermolecular β-amidosulfonylation of terminal alkynes using sodium sulfinates and quinoxalinone derivatives. The present methodology is compatible with a broad spectrum of various heterocyclic amides, terminal alkynes, and sodium sulfinates. It provides rapid access to valuable (Z)-β-amidovinyl sulfones at mild conditions. Moreover, the synthetic application of this methodology was demonstrated by the late-stage functionalization of numerous bioactive molecules.

Visible-Light Photoredox-Catalyzed Difunctionalization of Alkynes with Quinoxalin-2(1H)-Ones, P4S10, and Alcohols

“…On the basis of above-mentioned observations and previous literatures − , we proposed a possible mechanism for this multicomponent reaction (Scheme ). First, the interaction of P 4 S 10 3 with alcohol 4 produced O , O -dialkyl S -hydrogen phosphorodithioate 6 , which would generate thiyl radical 7 in air.…”

“…Difunctionalization of alkynes with simultaneous introduction of two functional groups into organic framework have been emerged as an attractive strategy for the synthesis of various substituted vinyl compounds in terms of their atom- and step-economic advantages. − Quinoxalin-2­(1 H )-ones are important structural moieties present in various natural products and biologically active molecules, which have attracted considerable synthetic interest owing to their diverse chemical profile and biological activities. − Recently, some quinoxalin-2­(1 H )-one-containing vinyl compounds have been synthesized through difunctionalization of alkynes (Scheme a–c), − including three-component trifluoromethylheteroaromatization of alkynes with quinoxalin-2­(1 H )-ones and CF 3 SO 2 Na or trifluoromethyl thianthrenium triflate (TT-CF 3 + OTf – ), difunctionalization of alkynes with quinoxalin-2­(1 H )-ones and sulfonyl reagents, and difunctionalization of alkynes with quinoxalin-2­(1 H )-ones and AgSCF 3 . Although encouraging progress has been made in this area, the development of new difunctionalization of alkynes for forging other important quinoxalin-2­(1 H )-one-containing vinyl compounds is still highly demanded in synthetic and medicinal chemistry.…”