Iron-catalyzed oxosulfonylation of alkynes with small-ring compounds and Na2S2O5 for the synthesis of β-keto sulfones

The ring-opening of small-ring compounds is an important topic in organic synthesis due to its ability to enable the reconstruction and reorganization of existing structures to form new skeletal units. In this paper, we report an iron-catalyzed multi-component reaction using alkynes, small ring compounds and Na(2)S(2)O5 for the synthesis of beta-keto sulfones, with the advantage of high chemoselectivity. In the reaction, Na(2)S(2)O5, which is cheap, stable and environmentally friendly, is used as the sulfur dioxide source to insert alkyl radicals to in situ generate alkyl sulfonyl radicals as the key intermediates for the oxosulfonylation of alkynes.