20244-61-5Relevant articles and documents
Scalable methodology for the catalytic, asymmetric α-bromination of acid chlorides
Dogo-Isonagie, Cajetan,Bekele, Tefsit,France, Stefan,Wolfer, Jamison,Weatherwax, Anthony,Taggi, Andrew E.,Lectka, Thomas
, p. 8946 - 8949 (2006)
The optimization of a practical, catalytic, asymmetric process for the α-bromination of acid chlorides to produce synthetically versatile, optically active α-bromoesters is reported. A range of products is produced in high enantioselectivity and moderate to good chemical yields with retention of both upon scale-up. The reactions herein are catalyzed by cinchona alkaloid derivatives, with the best performance achieved by the use of a proline cinchona alkaloid conjugate designed in a de novo fashion.
A mechanistic study on the catalytic, asymmetric α-bromination of acid chlorides
Dogo-Isonagie, Cajetan,Bekele, Tefsit,France, Stefan,Wolfer, Jamison,Weatherwax, Anthony,Taggi, Andrew E.,Paull, Daniel H.,Dudding, Travis,Lectka, Thomas
, p. 1091 - 1100 (2007)
The mechanism of the catalytic, asymmetric α-bromination of acid chlorides is probed through a series of crossover experiments, ion-pairing tests, and kinetic resolution studies to shed light on the factors that contribute to, and limit the production of, optically-active α-bromo esters. In order to understand better the observed sense of induction, as well as the high degree of enantiomeric excess exhibited by these products, extensive molecular modeling is employed on the relevant transition states. Finally, the usefulness of the α-bromo ester products is demonstrated by their simple derivatization into chiral epoxides. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
Peptide-Catalyzed Fragment Couplings that Form Axially Chiral Non-C2-Symmetric Biaryls
Coombs, Gavin,Sak, Marcus H.,Miller, Scott J.
supporting information, p. 2875 - 2880 (2020/01/24)
We have demonstrated that small, modular, tetrameric peptides featuring the Lewis-basic residue β-dimethylaminoalanine (Dmaa) are capable of atroposelectively coupling naphthols and ester-bearing quinones to yield non-C2-symmetric BINOL-type scaffolds with good yields and enantioselectivity. The study culminates in the asymmetric synthesis of backbone-substituted scaffolds similar to 3,3′-disubstituted BINOLs, such as (R)-TRIP, with good (94:6 e.r.) to excellent (>99.9:0.1 e.r.) enantioselectivity after recrystallization, and a diastereoselective net arylation of the minimally modified nonsteroidal anti-inflammatory drug (NSAID) naproxen.
Studies directed toward total synthesis of rhodocomatulins: A regioselective synthesis of brominated hydroxyanthraquinones by anionic annulations
Sk, Md Raja,Chakraborty, Soumen,Mal, Dipakranjan
, p. 309 - 317 (2018/02/09)
In this work, brominated hydroxyanthraquinones, which are the core structural motif of naturally occurring bromorhodocomatulins, were successfully synthesized using Hauser annulation reaction as the key step. When brominated Michael acceptors (brominated p-quinone monoketals) and cyanophthalides or bromocyanophthalides (Hauser donors) were reacted under the annulation conditions, brominated anthraquinones were obtained with 81–87% yields for four examples. On acidic quenching, products were obtained as solid which were separated by filtration and purified by recrystallization in acetone. No chromatography was required.
