Development of a Novel Approach to Formation of a Pyrrole Ring: Synthesis of 2,3,5-Substituted 1-[2-(Vinyloxy)ethyl]pyrroles

Reaction of 2-(vinyloxy)ethylisothiocyanate with unsaturated carbanions generated in situ from propargyl ethers and amines when treated with superbases, after S-alkylation and cyclization of the adducts in the presence of CuBr, leads to the previously unknown 2,3,5-substituted 1-[2-(vinyloxy)ethyl]pyrroles.     

Vinyl Ethers Containing an Epoxy Group: XXI. Synthesis and Acid-Catalyzed Cyclization of 1-[ω-(Vinyloxy)alkoxy]-3-(2-propynyloxy)-2-propanols- A Simple Route to 2-Propynyloxymethyl-Substituted Cyclic Polyethers

Base-catalyzed reaction of 2-[-(vinyloxy)alkoxy]methyloxiranes with 2-propynyl alcohol (3 wt % of t-BuOK, 60-85°C, 3-12 h) afforded first reperesentatives of the 1-[-(vinyloxy)alkoxy]-3-(2-propynyloxy)-2-propanol series in up to 99% yield. Treatment of 1-[2-(vinyloxy)ethoxy]- and 1-[2-(vinyloxy)ethoxyethoxy]-3-(2-propynyloxy)-2-propanols with trifluoroacetic acid (0.5 wt. %) in dry diethyl ether resulted in cyclization with formation of up to 96% of (2-methyl-1,3,6-trioxocan-4-yl)methyl- and (2-methyl-1,3,6,9-tetraoxacycloundecan-4-yl)methyl 2-propynyl ethers.     

Reaction of Red Phosphorus and Phosphine with Aryl(Hetaryl)Ethenes and -Ethynes

Abstract

Nucleophilic addition of phosphide anions generated from phosphorus red or phosphine to ethenes and ethynes in the presence of super bases to afford organylphosphines and -oxides has been performed.     

Generation of Phosphide Anions from Phosphorus Red and Phosphine in Strongly Basic Systems to Form Organylphosphines and -Oxides

Abstract

Generation of phosphide anions from phosphorus red or phosphine under the action of strong bases followed by their reactions with organyl halides, electrophilic alkenes and alkynes proves to be the most straightforward and well-controlled route to mono-, di- or triorganylphosphines or phosphine oxides of diverse structure.     

Regiospecific Functionalization of Dimetalated (1-Naphthyl)acetylene. Efficient Synthetic Procedures for Naphtho[2,1-b]chalcophenes

Treatment of (1-naphthyl)acetylene (1) with two mol equivalents of the BuLi-t-BuOK reagent in tetrahydrofuran/hexane, followed by successive addition of anhydrous lithium bromide, sulfur, selenium, or tellurium and t-butylalcohol gives naphtho[2,1-b]thiophene, -selenophene and -tellurophene in good yields. Reaction of dimetalated 1 with iodine or dimethyldisulfide afforded 2-iodo-, and 2-thiomethyl(1-ethylnyl)naphthalene.     

Reactions of Heterocumulenes with Organometallic Reagents: X. Quantum-Chemical Study of the Reaction of Aliphatic Isothiocyanates with Lithiated Allenes. Intramolecular Rearrangements of 1,3,4-Azatrienes

Study of the potential energy surface for the reaction of isothiocyanates with -lithiated allenes showed that the formation of 1,3,4-azatriene occurs in one step through a four-center transition state. [1,5]-Sigmatropic rearrangements of 1,3,4-azatrienes and electrocyclizations of the resulting conjugated 1,3,5-azatriene systems lead to formation of dihydropyridine ring. Pyrrole structures are more likely to arise from protonation of 3-alkoxy-1,3,4-azatriene.