61415-38-1Relevant academic research and scientific papers
Fritsch-Buttenberg-Wiechell rearrangement of magnesium alkylidene carbenoids leading to the formation of alkynes
Ando, Akane,Imafuji, Aki,Kimura, Tsutomu,Sekiguchi, Koto
, p. 1352 - 1359 (2021/06/06)
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 using13C-labeled sulfoxides and by using DFT calculations.
An Experimental and Computational Investigation of (α-Methylbenzylidene)carbene
Yang, Xi,Languet, Keith,Thamattoor, Dasan M.
, p. 8194 - 8198 (2016/09/28)
Photolysis of 1-(1-phenylethylidene)-1a,9b-dihydro-1H-cyclopropa[l]phenanthrene, in C6H6 (or C6D6), at ambient temperature, produces (α-methylbenzylidene)carbene which undergoes a facile Fritsch-Buttenberg-Wiechell (FBW)-type rearrangement to 1-phenylpropyne. The alkyne results exclusively from a 1,2-phenyl shift as evident from the use of a 13C-labeled precursor. This experimental result is consistent with CCSD(T)/cc-pVTZ//B3LYP/6-31+G? calculations which reveal that a 1,2-phenyl shift in the singlet carbene needs to overcome a barrier of only 3.8 kcal/mol whereas the 1,2-methyl shift has to surmount a much larger barrier of 11.9 kcal/mol. The alkyne remains the predominant product when the photolysis is carried out in cyclohexene but the carbene-alkene cycloadduct could be detected, albeit in low yield, in the photolysate.
