Two classes of addition/cycloaddition cascade reactions of hydrazinecarbodithioate (1) have been developed under mild reaction conditions. Reaction of hydrazinecarbodithioate (1) with formaldehyde solution (2) and propiolic acid (3) gives 3-propargyl-5-thiol-2,3-dihydro-1,3,4-thiadiazoles (5) via a decarboxylative coupling/cycloaddition domino sequence. When propiolic acid (3) is switched to ph...

The biosynthesis of dimeric pyrrole-imidazole alkaloids is likely mediated by enzyme-catalyzed reversible single-electron transfer (SET) cycloaddition. We now show that Ir(ppy)3 can promote SET-mediated formal [2+2] and [4+2] cycloaddition reactions of pyrrole-imidazole alkaloids-related substrates under photolytic conditions. This biomimetic approach is useful for the construction of the core ...

A catalytic amount of tin(IV) chloride catalyzed formal [4+2] cycloaddition reaction of di-tert-butyl 2-ethoxycyclobutane-1,1-carboxylate with ketones or aldehydes to give diethyl 6-ethoxydihydro-2H-pyran-3,3(4H)-dicarboxylates, whereas two equivalents of trimethylsilyl triflate promoted tandem [4+2] cycloaddition and lactonization to afford 3-oxo-2,6-dioxabicyclo[2.2.2]octane-4-carboxylate est...

A highly reactive Ag(I)-catalyzed [3 + 2] cycloaddition of azomethine ylides is founded using AgOAc as the catalytic precursor and phosphines as ligands. Using a new bis-ferrocenyl amide phosphine (FAP) as the ligand, we found that high enantioselectivities (up to 97% ee) have been achieved in the [3 + 2] cycloaddition of azomethine ylides. Up to four stereogenic centers can be established in t...

A variety of 4-phosphinylpyrrolidin-3-ones was prepared via a [3+2] cycloaddition between aryl aldonitrones and phosphinylallenes. The products were isolated as unique 4,5-trans diastereomers, in yields up to 80% over 23 examples. In the case chiral racemic allenes, 2:1 4:1 moderate 2,5-diastereoselectivity observed. Under reaction conditions, cycloadducts directly undergo rearrangement afford ...