A phosphine-catalyzed [3+2] annulation reaction of α-substituted allenoates with ester-activated α,β-unsaturated imines is reported, which provides new and efficient access to highly functionalized cyclopentenes bearing one all-carbon quaternary center. This reaction also expands the scope of the famous Lu [3+2] cycloaddition reaction.

Intramolecular [2+2] photocycloaddition of aromatic chain imides possessing bis-phenanthrene moieties afforded straight and cross ring closure products. The ratio of cycloadducts was dependent on reaction time and temperature, which resulted in a reversal of regioselectivity. The reaction was proved to involve a retro cycloaddition. The cross ring closure products were formed predominantly in t...

A formal, metal-free, [2 + 2 + 2] cycloaddition strategy is described based on a cascade of two pericyclic processes. The first step involves an intramolecular propargylic ene reaction of a 1,6-diyne to generate a vinylallene, which then reacts in an inter- or intramolecular Diels-Alder reaction with an alkenyl or alkynyl dienophile. Reactions involving unsymmetrical alkenyl and alkynyl dienoph...

Cycloaddition reactions between 1,3-butadiene and the C-terminated SiC(1 0 0)-c(2 · 2) surface have been addressed using quantum-chemical methods. The c(2 · 2) structure consists of ACBCA bridges between underlayer Si atoms which themselves form SiASi bonds. Of various possible reaction products, the one formed by a [2+ 4] reaction with the ACBCA bridge (giving a species resembling 1,4-cyclohex...

The intramolecular [4+2] cycloaddition between arenes and allenes first reported by Himbert gives rapid access to rigid polycyclic scaffolds. Herein, we report a one-pot oxyalkynylation/cycloaddition reaction proceeding under mild conditions (23–90 °C) providing complex architectures with high efficiency, atom step economy. bicyclo[2.2.2]octadiene products were obtained wide variety of useful f...

Cycloaddition reactions between 1,3-butadiene and the C-terminated SiC(1 0 0)-c(2 · 2) surface have been addressed using quantum-chemical methods. The c(2 · 2) structure consists of ACBCA bridges between underlayer Si atoms which themselves form SiASi bonds. Of various possible reaction products, the one formed by a [2+ 4] reaction with the ACBCA bridge (giving a species resembling 1,4-cyclohex...

We describe here a Tf₂NH-catalyzed formal (3+3) cycloaddition of silyl enol ethers with acrylates as a new domino reaction. In the domino sequence, the catalyst activates Michael addition, deprotonation of the resulting silyloxonium cation and intramolecular Claisen condensation. It was found that reaction modes significantly depend on the reaction temperature. We also examined the mechanistic ...

Drug-like spirocyclic scaffolds have been prepared by fusing fully functionalized pyrrolidine with oxindoles in an approach based on 1,3-dipolar cycloaddition. Reaction between aziridine and 3-ylideneoxindole generated diverse spirooxindole-pyrrolidines in good yield (up to 95%) with high diastereoselectivity (up to >20:1). The reaction also proceeded smoothly with several other synthetically u...

the dual diene/1,3-dipolar character of 1-h-imidazole 3-oxide, hio 1, allows this compound toparticipate in a competitive diels-alder (da)/1,3-dipolar cycloaddition (13dc) reaction toward c=sdouble bond of the electro-deficient sulfonyl methane sfm 2. the b3lyp/6-311++g(d,p) calculatedrelative gibbs free energies indicate that among the studied 13dc and da reactions, former iscompletely preferr...