Catalytic enantioselective bromoamination of allylic alcohols

Abstract

An enantioselective bromoamination of allylic alcohols has been developed for the first time using a newly designed cinchona-derived thiourea as the catalyst and N,N-dibromo-4-nitrobenzenesulfonamide as a bromine and amine source.

Catalytic Asymmetric Bromination of Unfunctionalized Olefins with H2O as a Nucleophile

“…Although asymmetric halogenation had proven to be highly challenging, significant progress has been made in recent years 1–3. For the intermolecular process,4 great success has been achieved with olefin substrates containing various functional groups 5–11. However, for unfunctionalized olefins, asymmetric halogenation presents new challenges, owing to the lack of directing groups, and only limited examples have been reported, primarily with carboxylic acids as nucleophiles 9.…”

Highly Enantioselective Intermolecular Iodo- and Chloroamination of Enecarbamates Catalyzed by Chiral Phosphoric Acids or Calcium Phosphate Salts

“…11 Recently, Zhou et al developed an enantioselective bromoamination of allylic alcohols reaction using thiourea-derived cinchona as catalyst. 12 In continuation of our studies on enantioselective vicinal difunctionalization of enecarbamates, 13 we herein report the first highly enantioselective intermolecular iodo-and chloroamination of enecarbamates with up to 99% enantiomeric excess and synthetically useful yields (Scheme 1). SYNLETT0 9 3 6 -5 2 1 4 1 4 3 7 -2 0 9…”

Synthesis of Enantioenriched Bromohydrins via Divergent Reactions of Racemic Intermediates from Anchimeric Oxygen Borrowing

“…Recent work from Borhan et al offered a higher resolution of such reaction’s mechanistic picture, in which the “nucleophile-assisted alkene activation” plays a key role . In sharp contrast, less successful examples have been reported on its intermolecular counterpart. , By employing “activable” nucleophiles (for instance, carboxylic acids), which can be easily directed and/or activated by the catalyst, a couple of transformations have been realized . For halofunctionalizations with “inert” nucleophiles lacking coordination to the catalyst, the task becomes even more formidable (Figure a).…”