Formation of P-Ylide under Neutral and Metal-Free Conditions: Transformation of Aziridines and Epoxides to Conjugated Dienes In the Presence of Phosphine

Phosphine Organocatalysis

The hallmark of nucleophilic phosphine catalysis is the initial nucleophilic addition of a phosphine to an electrophilic starting material, producing a reactive zwitterionic intermediate, generally under mild conditions. In this Review, we classify nucleophilic phosphine catalysis reactions in terms of their electrophilic components. In the majority of cases, these electrophiles possess carbon-carbon multiple bonds: alkenes (section 2), allenes (section 3), alkynes (section 4), and Morita-Baylis-Hillman (MBH) alcohol derivatives (MBHADs; section 5). Within each of these sections, the reactions are compiled based on the nature of the second starting material-nucleophiles, dinucleophiles, electrophiles, and electrophile-nucleophiles. Nucleophilic phosphine catalysis reactions that occur via the initial addition to starting materials that do not possess carbon-carbon multiple bonds are collated in section 6. Although not catalytic in the phosphine, the formation of ylides through the nucleophilic addition of phosphines to carbon-carbon multiple bond-containing compounds is intimately related to the catalysis and is discussed in section 7. Finally, section 8 compiles miscellaneous topics, including annulations of the Hüisgen zwitterion, phosphine-mediated reductions, iminophosphorane organocatalysis, and catalytic variants of classical phosphine oxide-generating reactions.

Wittig olefination between phosphine, aldehyde, and allylic carbonate: a general method for stereoselective synthesis of trisubstituted 1,3-dienes with highly variable substituents

A clean and salt-free Wittig olefination between phosphines, aldehydes, and allylic carbonates is described. It represents a general method for convenient and efficient synthesis of 1,2,4-trisubstituted 1,3-dienes from readily available starting materials. This method exhibits high synthetic efficiency, high stereoselectivity, and high variability of substituent.

Unexpected transfer of tosyl group of ArCH=NTs-catalyzed by N-heterocyclic carbene

Reactions of N-tosylimines with aziridines and electron-deficient unsaturated compounds in the presence of catalytic amount of NHC afforded unexpected tosyl group transfer products in good to high yields, which represent a new reaction pattern for imines as well as for catalysis of NHC.

New directions for the Morita−Baylis–Hillman reaction; homologous aldol adducts via epoxide opening

Under trialkylphosphine catalyzed Morita-Baylis-Hillman reaction conditions, epoxides react with enones to give rise to homologous aldol adducts.