in the recent work, the reaction mechanism between triphenylphosphine 1, dialkyl acetylenedicarboxylates 2 in the presence of nh-acid, such as 5-aminoindazole 3 were investigated theoretically. quantum mechanical studies were performed for evaluation of potential energy surfaces of all structures participated in the reaction mechanism both in gas phase and in dichloromethane. the first step of ...

The reaction of 3,3-dichloro-2,2,4,4-tetramethylcyclobutanethione (1) with diazo compounds yielded spirocyclic 2,5-dihydro-1,3,4-thiadiazoles 3, which decomposed at ca. 45°C to give the corresponding thiocarbonyl ylide of type 4. In the absence of trapping agents, these thiocarbonyl ylides underwent a 1,3-dipolar electrocyclization to yield spirocyclic thiiranes 5. On the other hand, the thioca...

In this study, several dearomative reactions of N-aromatic zwitterions were carried out to determine the factors controlling site selectivity. A series organometallic species applied as nucleophiles for additions, which revealed that chelation between metal and nitrogen anion dominantly affected selectivity reaction in zwitterions. cascade process, involving addition followed by intermolecular ...

2-Acetylcyclopentanone undergoes a smooth reaction with triphenylphosphine and dialkyl acetylenedicarboxylates to produce dialkyl 2-(1-acetyl-2-oxocyclopentyl)-3-(1,1,1-triphenyl-lambda(5)-phosphanylidene)succinates. These compounds undergo intramolecular Wittig reactions in boiling benzene to produce highly strained spirocyclobutene derivatives, which spontaneously undergo ring-opening reactio...