Preparation of Alkenyl Sulfides by the Olefination of Thiolesters Using Thioacetals

Abstract

The reaction of thiolesters with titanocene alkylidenes prepared by the treatment of thioacetals with the low valent titanium species Cp2Ti[P(OEt)3]2 produced the corresponding alkenyl sulfides in good yields with moderate to good Z stereoselectivity.

Titanium reagents for the alkylidenation of carboxylic acid and carbonic acid derivatives

“…titanium reagents that will alkylidenate esters 82 and thioesters. 83 The active species are almost certainly titanium alkylidenes as they catalyse alkene metathesis, 84-87 add to alkynes 88 and nitriles, 89 and can cyclopropanate alkenes. 90 Takeda and Fujiwara have discussed their work on desulfurisation of thioacetals and its applications in 1999.…”

The Society for Cardiovascular Angiography and Interventions' 27th Annual Scientific Sessions

“…As expected, the alkylidenetitanocenes 2 generated by the reaction of saturated diphenyl thioacetals 9 with the titanocene(II) species 8 reacted with aldehydes and ketones to produce di‐ and trisubstituted olefins 10 via the formation of oxatitanacyclobutane intermediates 11 (Scheme ) 13. Similarly to the foregoing carbonyl olefinations using titanium carbene complexes, the reaction was successfully applied to the transformation of a wide variety of carboxylic acid derivatives into enol ethers,13 vinyl sulfides,14 and enamines 15…”

Cyclopropanation and Carbonyl Olefination Utilizing 2-(Alk-1-yn-1-yl)-2-(trialkylsilyl)-1,3-dithianes via Regioselective Generation of Titanium Alkynylcarbene Complexes

“…It is also of special interest that every reaction examined gave a single stereoisomer. Olefination of carboxylic acid derivatives utilizing a thioacetal−titanocene(II) system generally produces Z stereoisomers, in which there is less steric interaction between the alkyl group originating from the acyl group and the alkyl substituent at the β carbon . Therefore, it is reasonable to assume that the configuration of these enol ethers is E .…”