A metal‐free hydrosulfonylation of electron‐deficient alkynes with sodium sulfinates or sulfinic acids to access both E‐ and Z‐β‐sulfonyl‐α,β‐unsaturated carbonyl compounds has been developed. We propose that this reaction via a hydroxylallene intermediate delivers the thermodynamically stable E isomer, or via a concerted termolecular AdE3 mechanism affords Z isomer. The stereoselectivity of addition (syn or anti) can be controlled by varying the sulfonyl sources and acidic buffer solutions. This protocol exhibits broad substrate scope for internal or terminal alkynes including various substituted ynones and alkynyl esters. This approach is mild, efficient, operationally simple and easy to be scaled‐up.magnified image

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Wie im Formelschema skizziert, erhält man die Labetalolstereoisomeren (VI) und (VII) über die Aminoketone (V).

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