Tributylphosphine-catalyzed ring-opening reaction of epoxides and aziridines with acetic anhydride

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.

Heterogeneous Acidic and Eco-Friendly Reagents for Mild and Convenient Conversion of Epoxides to 1,2-Diacetates

A highly regioselective ring-opening of epoxides with acetic anhydride in the presence of hydrated disodium hydrogen phosphate and sodium hydrogen sulfate as efficient and eco-friendly reagents is described. The reactions are clean and lead to 1,2-diacetates in high to excellent yields.

A Mild and Regioselective Ring-Opening of Aziridines with Acid Anhydride Using TBD or PS-TBD as a Catalyst

The ring-opening of N-tosylaziridines with various acid anhydrides catalyzed by 5 mol % of 1,5,7-triazabicyclo[4,4,0]dec-5-ene (TBD) afforded the corresponding β-amino esters in excellent yields under mild reaction conditions. Polymer-supported catalyst, PS-TBD also acts as a good catalyst for this reaction. PS-TBD was easily recovered and reused with minimal loss of activity.

Regio- and stereoselective synthesis of new diaminocyclopentanols

The optimal conditions for regio- and stereoselective epoxide ring opening of N,N-disubstituted 1,2-epoxy-3-aminocyclopentanes by different nucleophilic reagents have been developed. The substituents on the nitrogen atom in the epoxide precursor and the orientation of the oxirane ring are crucial for the reaction outcome. Thus, treatment of (1RS,2SR,3SR)-1,2-epoxy-3-(N,N-dibenzylamino)cyclopentane (3b) with amines gave a mixture of C1 and C2 regioadducts, while the use of (1RS,2SR,3SR)-1,2-epoxy-3-(N-benzyl-N-methylamino)cyclopentane (3a) led ultimately to C1 adducts. Base-catalyzed aminolysis of epoxides 6a,b afforded mainly C1 adducts 13a,b arising from trans-diaxal opening of the epoxide ring. Using a Lewis acid catalyst, epoxides 6a,b were transformed into diaminocyclopentanols 14a,b via an alternative pathway involving the formation of aziridinium intermediate 17.

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.

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

A general approach to formation of the P-ylide from the reaction of aziridines or epoxides with organophosphine under neutral and metal-free conditions is realized. Conjugated diene derivatives based on this kind of P-ylide were prepared in a facile and convenient way.

Facile Preparation of β-Fluoro Amines by the Reaction of Aziridines with Potassium Fluoride Dihydrate in the Presence of Bu4NHSO4

Potassium fluoride combined with tetrabutylammonium bisulfate is an efficient reagent to convert a variety of aziridines derived from cyclic and acyclic alkenes to beta-fluoro amine derivatives in high yield.