Use of Substituted 3-Sulfolenes as Precursors for 1,3-Butadienes

Highly Regio- and Stereoselective Catalytic Synthesis of Conjugated Dienes and Polyenes

“…9,10 Although sulfolenes can be α-alkylated and then converted to dienes by heating at elevated temperatures, typically 150–200 °C or by flash vacuum pyrolysis, this stepwise approach is unselective, inefficient, incompatible with many functional groups, and cannot be used to introduce aryl and vinyl substituents. 10 We envisioned that a combination of a regio- and stereoselective baseinduced ring opening of sulfolenes (e.g., sulfolene 1 to sulfinate 2 , Scheme 1, part B) and a subsequent desulfitative Pd-catalyzed coupling (Scheme 1, part C) would result in a direct, regio- and stereoselective dienylation. Indeed, the sulfolene ring opening reaction proceeds regio- and stereoselectively and affords sulfinates 3 from 2-substituted sulfolenes 4 , and sulfinates 5 from 3-substituted sulfolenes 6 .…”

Recent trends in isomeric thienoquinoxalines [1980‐2000]

“…Treatment of the chloride 68b with hydrazine produced the hydrazide 69, which was converted to triazolo derivatives 70a (using carbon disulfide) and 70b (using diethyl malonate), and tetrazolo derivative 71 with nitrous acid, respectively [36] Compound 5 underwent smooth deprotonation/alkylation reactions [43,44] in relatively lower yields. Tetraalkylated 94, 95 and trimethylated derivatives 96 were obtained when 5 was treated with excess amount of n-butyllithium and alkyliodide.…”

Competition for regiochemical control between substituents of some 2,3-disubstituted buta-1,3-dienes in the Diels–Alder reactions

“…A rapid isomerization of lc' to lc must be taking place during the reaction. 7 The method shown in Table 1 was not applicable to the synthesis of ld12 nor l e because of undesired side reactions during the oxidation stage -11 Alternatively, compounds Id and l e were prepared from 3-methoxycarbonyl-4-sulfolanone 513 by treatment with toluene-p-sulfonyl chloride (TsC1) or acetyl chloride (AcCl), respectively [eqn. ( 3 These are isolated yields after column chromatography.…”