Ring﹐pening under basic conditions occurs in a regime of strong interaction between the nucleophile (OH– ) and the epoxide and the interaction is governed by the steric (Pauli) repulsion. The latter steers the attack preferentially towards the sterically less encumbered Cβ . Under acidic ...
Ring-opening of epoxides with basic nucleophiles Epoxides are cyclic ethers with considerable ring strain (about 13 kcal/mol) Epoxides undergo reaction with nucleophiles under basic conditions at theleast substitutedend of the epoxide If a chiral center is at this carbon, its stereochemistry will be ...
Their polymerization by anionic and by related nucleophilic ring-opening reactions is described and discussed in this chapter. The mechanisms of initiation, propagation, and transfer reactions in the presence of ionic initiators, typically alkali metal derivatives, and their impact on the polyether ...
opening of the epoxide ring is statistically equal on both sides, the rearranged product may have the two carbonyl groups on either side of the original carbon atoms of the two epoxide rings, both completely opened. MS of the rearranged products reveals that the ring opening is approximately ...
Selective ring opening of 204 may be explained by assuming the assistance of the neighboring N-acetyl group at C-1, suggesting that 205 possesses the (1,4,5/2,3)-configuration. Therefore, an attempt was made to convert the spiro epoxide into the exo-alkene 207, which was expected to be...
a weakly basic mixed cyanocuprate of Li-TIPS-propyne proved the reagent of choice: Eliminations were largely avoided, the scyllo† -2,4,6-tris(TIPS-propargyl)cyclohexane-1,3,5-triol (13a), obtained in a stereoselective one-pot threefold epoxide opening (up to 69%), allowed the pertinen...
This cycloaliphatic tertiary amine has a sufficiently high basicity and nucleophilicity to catalyze the ring opening of the epoxides with the mercaptans but it undergoes no undesired secondary reactions, for example with the epoxide. Moreover, the composition according to the invention comprises less ...
Polyether polyols generated by the ring-opening polymerization of epoxides are widely utilized as intermediates in the preparation of polyurethane foams, elastomers, sealants, coatings, and the like. The reaction of epoxides with alcohols provides glycol ethers, which may be used as polar solvents in...
Abenhaim D, Loupy A, Mahieu C, Semeria D (1994) Ring opening of a fatty epoxide by diethylacetamido malonate in basic medium by phase transfer catalysis or under microwave irradiation. Synth Commun 24:1809–1816Abenhaïm D, Loupy A, Mahieu C, Séméria D ( 1994) ) Synth Commun 24:...
The high reactivity of epoxides makes them crucial intermediates in the synthesis of various organic compounds, including polymers, through reactions such as ring-opening polymerization. Epoxy resins, products of epoxides, are known for their exceptional mechanical properties, chemical resistance, and adhes...