Related Experiment Video
Updated: Jul 26, 2025

Unraveling Entropic Rate Acceleration Induced by Solvent Dynamics in Membrane Enzymes
Published on: January 16, 2016
Surmounting Byproduct Inhibition in an Intermolecular Catalytic Asymmetric Alkene Bromoesterification Reaction as
D Christopher Braddock1, Ben M J Lancaster1, Christopher J Tighe2
1Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, White City Campus, 82 Wood Lane, London W12 0BZ, U.K.
Abstract:
Kinetic profiling has shown that a (DHQD)2PHAL-catalyzed intermolecular asymmetric alkene bromoesterification reaction is inhibited by primary amides, imides, hydantoins, and secondary cyclic amides, which are byproducts of common stoichiometric bromenium ion sources. Two approaches to resolving the inhibition are presented, enabling the (DHQD)2PHAL loading to be dropped from 10 to 1 mol % while maintaining high bromoester conversions in 8 h or less. Iterative post-reaction recrystallizations enabled a homochiral bromonaphthoate ester to be synthesized using only 1 mol % (DHQD)2PHAL.
More Related Videos
Related Concept Videos
Radical Anti-Markovnikov Addition to Alkenes: Overview
Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
Regioselectivity of Electrophilic Additions-Peroxide Effect
Regioselectivity and Stereochemistry of Hydroboration
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...
Radical Substitution: Allylic Bromination
Hydroboration-Oxidation of Alkenes

