Chiral bora[1]ferrocenophanes: syntheses, mechanistic insights, and ring-opening polymerizations

Saeid Sadeh1, Hridaynath Bhattacharjee, Elaheh Khozeimeh Sarbisheh

  • 1Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9 (Canada), Fax: (+1) 306 966 4730.

Related Concept Videos

Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)01:16

Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)

Ring-opening metathesis polymerization or ROMP involves strained cycloalkenes as starting materials. The mechanism of ROMP proceeds by reacting cycloalkene with Grubbs catalyst to give metallacyclobutane intermediate which undergoes a ring-opening reaction to form new carbene. The new carbene reacts with another molecule of cycloalkene. Repetition of these steps leads to the formation of an unsaturated open-chain polymer product. All these steps are reversible, however, relieving the ring...
2.3K
Base-Catalyzed Ring-Opening of Epoxides02:26

Base-Catalyzed Ring-Opening of Epoxides

Due to their highly strained structures, epoxides can readily undergo ring-opening reactions through nucleophilic substitution, either in the presence of an acid or a base. The nucleophilic substitution reactions in the presence of acid are called acid-catalyzed ring-opening reactions, and nucleophilic substitution reactions in the presence of a base are called base-catalyzed ring-opening reactions. Epoxides undergo base-catalyzed ring-opening reactions in the presence of a strong nucleophile...
8.5K
Acid-Catalyzed Ring-Opening of Epoxides02:24

Acid-Catalyzed Ring-Opening of Epoxides

Epoxides that are three-membered ring systems are more reactive than other cyclic and acyclic ethers. The high reactivity of epoxides originates from the strain present in the ring. This ring strain acts as a driving force for epoxides to undergo ring-opening reactions either with halogen acids or weak nucleophiles in the presence of mild acid. The acid catalyst converts the epoxide oxygen, a poor leaving group, into an oxonium ion, a better leaving group, making the reaction feasible. The...
6.9K
Regioselectivity and Stereochemistry of Hydroboration02:36

Regioselectivity and Stereochemistry of Hydroboration

A significant aspect of hydroboration–oxidation is the regio- and stereochemical outcome of the reaction.
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn...
7.7K
ortho–para-Directing Activators: –CH3, –OH, –⁠NH2, –OCH301:11

orthopara-Directing Activators: –CH3, –OH, –⁠NH2, –OCH3

All ortho–para directors, excluding halogens, are activating groups. These groups donate electrons to the ring, making the ring carbons electron-rich. Consequently, the reactivity of the aromatic ring towards electrophilic substitution increases. For instance, the nitration of anisole is about 10,000 times faster than the nitration of benzene. The electron-donating effect of the methoxy group in anisole activates the ortho and para positions on the ring and stabilizes the corresponding...
4.8K