Enantioselective bromocyclization of allylic amides catalyzed by BINAP derivatives.

Org Lett

School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.

Published: March 2015

A highly enantioselective bromocyclization of allylic amides with N-bromosuccinimide (NBS) was developed with DTBM-BINAP as a catalyst, affording chiral oxazolines with a tetrasubstituted carbon center in high yield with up to 99% ee. By utilizing the bromo substituent as a handle, the obtained compounds were converted to synthetically useful chiral building blocks.

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.orglett.5b00220DOI Listing

Publication Analysis

Top Keywords

enantioselective bromocyclization
8
bromocyclization allylic
8
allylic amides
8
amides catalyzed
4
catalyzed binap
4
binap derivatives
4
derivatives highly
4
highly enantioselective
4
amides n-bromosuccinimide
4
n-bromosuccinimide nbs
4

Similar Publications

Scavengers that capture reactive chemical substances are used to prevent the decomposition of materials. However, in the field of catalysis, the development of scavengers that inhibit background pathways has attracted little attention, although the concept will open up an otherwise inaccessible reaction space. In catalytic bromination, fast non-catalyzed background reactions disturb the catalytic control of the selectivity, even when using N-bromoamide reagents, which have a milder reactivity than bromine (Br ).

View Article and Find Full Text PDF

We describe regio- and enantioselective bromocyclization of difluoroalkenes catalyzed by chiral bisphosphine oxides. Owing to the simultaneous activation of both the brominating reagent and amide substrate, the desired cyclization reaction proceeds smoothly even at low temperature to provide bromodifluoromethyl-containing oxazolines with a chiral quaternary center in a highly enantioselective fashion (up to 99% ee). This protocol features the use of commercially available brominating reagents and readily accessible chiral catalysts.

View Article and Find Full Text PDF

Difluoromethylene-containing compounds have attracted substantial research interest over the past decades for their ability to mimic biological functions of traditional functional groups while providing a wide variety of pharmacological benefits bestowed by the C-F bond. We report a novel strategy to access RCFBr-containing heterocycles by regio- and enantioselective bromocyclization of difluoroalkenes enabled by chiral anion phase-transfer catalysis. The utility of this methodology was highlighted through a synthesis of an analogue of efavirenz, a drug used for treating HIV.

View Article and Find Full Text PDF
Article Synopsis
  • The study explores new methods for enantioselective bromolactonization of trisubstituted olefinic acids, which produce chiral lactones with two asymmetric centers.
  • This research highlights the successful application of 5-exo and 6-endo bromocyclization using N-bromosuccinimide and a pyridyl phosphoramide catalyst for the first time.
  • It also reveals how factors such as the basicity of pyridine and the presence of N-H protons in the catalyst significantly impact the reactivity and enantioselectivity of the reactions.
View Article and Find Full Text PDF

We report a chiral phosphoric acid catalyzed bromocyclization/regiodivergent reaction of racemic intermediates sequence, which is enabled by anchimeric oxygen borrowing. Different types of alkenes are applicable, and both enantiomers of the bromohydrin products were obtained in generally excellent yields and enantioselectivities. In addition, an example of enantioconvergent synthesis from the two isomeric products is presented.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!