Sulfoxide Synthesis from Sulfinate Esters under Pummerer-like Conditions

A facile synthetic method of allyl sulfoxides by <i>S</i>-allylation of sulfinate esters through sulfonium intermediates has been developed without [3,3]-sigmatropic rearrangement and further Pummerer-type reactions of the resulting allyl sulfoxides. On the basis of the plausible reaction mechanism involving sulfonium salt intermediates, S-alkynylation and S-arylation were also accomplished.<br>

Sulfoxide Synthesis from Sulfinate Esters under Pummerer-like Conditions

A facile synthetic method of allyl sulfoxides by <i>S</i>-allylation of sulfinate esters through sulfonium intermediates has been developed without [3,3]-sigmatropic rearrangement and further Pummerer-type reactions of the resulting allyl sulfoxides. On the basis of the plausible reaction mechanism involving sulfonium salt intermediates, S-alkynylation and S-arylation were also accomplished.<br>

Sulfoxide synthesis from sulfinate esters under Pummerer-like conditions

A facile synthetic method of allyl sulfoxides by S-allylation of sulfinate esters proceeds through sulfonium intermediates. On the basis of the plausible reaction mechanism, S-alkynylation and S-arylation were also accomplished.

Efficient Synthesis of Sulfinate Esters and Sulfinamides via Activated­ Esters of p-Toluenesulfinic Acid

Sulfinate esters were prepared by the process of activating p-toluenesulfinic acid with either cyanuric chloride, methanesulfonyl chloride, or 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC-HCl). Activation of p-toluenesulfinic acid with cyanuric chloride led to the formation of sulfinate esters that were accompanied by the formation of the corresponding sulfones. The use of methanesulfonyl chloride for activation via methanesulfonic p-toluenesulfinic anhydride afforded mixtures of sulfinate esters and methanesulfonates. The use of the carbodiimide EDC proved to yield the best results with the highly selective formation of the target sulfinate esters. The use of trimethylacetic p-toluenesulfinic anhydride or cyanuric chloride to achieve the synthesis of sulfinamides proved to be ineffective due to poor chemoselectivity of the nucleophilic attack on the activated p-toluenesulfinic acid anhydride. Ultimately, the use of EDC-HCl to form the sulfinamides proved to be the best pathway for synthesis.

The [2,3]-sigmatropic rearrangement of propargylic sulfonates to allenic sulfones and further applications to oxacycles and dihydrofuranones

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] The scope of [2,3]-sigmatropic rearrangement of propargylic sulfinates to allenic sulfones by silver catalysis was expanded. A series of new propargylic sulfinate esters was generated from a variety of aromatic and heteroaromatic sulfonyl chlorides and their rearrangement to allenic sulfones is reported. In addition, the synthesis of propargylic sulfinate esters containing electron-withdrawing benzenesulfonyl chlorides was optimized and reported. In the course of pursuing a Nazarov cyclization of allenyl vinyl ketones (AVK), we discovered multiple new reactions. Allenyl alcohols underwent an intramolecular cyclization to 2,5-dihydrofurans in the presence of Fetizon's reagent and this process was then optimized using silver fluoride. The methodology was expanded to synthesize higher membered oxacycles also. A tandem cyclization of hydroxypropargylic sulfinate esters to 2,5-hydrofurans was also developed. A new synthesis of a'-hydroxyenones was developed by the oxidation of a-allenyl alcohols with Cr (VI) regents and then extended to synthesize dihydrofuran- 3(2H)-ones by acid catalysis.