A series of 1-heteroatom-substituted vinyl p-tolyl sulfoxides were prepared and treated with organometallic reagents to evaluate which combination of sulfoxides and organometallic reagents yielded alkynes the most efficiently. The use of 1-chlorovinyl p-tolyl sulfoxide and isopropylmagnesium chloride was optimal for this purpose. A variety of 1-chlorovinyl p-tolyl sulfoxides were prepared from carbonyl compounds and chloromethyl p-tolyl sulfoxide and were converted into alkynes via the sulfoxide/magnesium exchange reaction and subsequent Fritsch–Buttenberg–Wiechell (FBW) rearrangement of the resulting magnesium alkylidene carbenoids. The mechanism of the FBW rearrangement of magnesium alkylidene carbenoids was studied by using 13C-labeled sulfoxides and by using DFT calculations.

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A method for generating alkynylmagnesium chlorides from 1-chlorovinyl p-tolyl sulfoxides and an isopropylmagnesium chloride-lithium chloride complex (turbo Grignard reagent) has been developed. The method consists of a sulfoxide/magnesium exchange reaction of 1-chlorovinyl p-tolyl sulfoxides and a turbo Grignard reagent, a FritschButtenbergWiechell rearrangement of the resulting magnesium alkylidene carbenoids, and a deprotonation of terminal alkynes with a turbo Grignard reagent. The resulting alkynylmagnesium chlorides are reacted with a variety of electrophiles to generate internal alkynes.

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