78024-74-5Relevant articles and documents
Enantioselective Desymmetrization of 2-Aryl-1,3-propanediols by Direct O-Alkylation with a Rationally Designed Chiral Hemiboronic Acid Catalyst That Mitigates Substrate Conformational Poisoning
Estrada, Carl D.,Ang, Hwee Ting,Vetter, Kim-Marie,Ponich, Ashley A.,Hall, Dennis G.
supporting information, (2021/04/07)
Enantioselective desymmetrization by direct monofunctionalization of prochiral diols is a powerful strategy to prepare valuable synthetic intermediates in high optical purity. Boron acids can activate diols toward nucleophilic additions; however, the design of stable chiral catalysts remains a challenge and highlights the need to identify new chemotypes for this purpose. Herein, the discovery and optimization of a bench-stable chiral 9-hydroxy-9,10-boroxarophenanthrene catalyst is described and applied in the highly enantioselective desymmetrization of 2-aryl-1,3-diols using benzylic electrophiles under operationally simple, ambient conditions. Nucleophilic activation and discrimination of the enantiotopic hydroxy groups on the diol substrate occurs via a defined chairlike six-membered anionic complex with the hemiboronic heterocycle. The optimal binaphthyl-based catalyst 1g features a large aryloxytrityl group to effectively shield one of the two prochiral hydroxy groups on the diol complex, whereas a strategically placed "methyl blocker"on the boroxarophenanthrene unit mitigates the deleterious effect of a competing conformation of the complexed diol that compromised the overall efficiency of the desymmetrization process. This methodology affords monoalkylated products in enantiomeric ratios equal or over 95:5 for a wide range of 1,3-propanediols with various 2-aryl/heteroaryl groups.
Oxidative Coupling of Aryl Boron Reagents with sp3-Carbon Nucleophiles: the Enolate Chan-Evans-Lam Reaction
Moon, Patrick J.,Halperlin, Heather M.,Lundgren, Rylan J.
supporting information, p. 1894 - 1898 (2016/08/31)
Reported is a versatile new oxidative method for the arylation of activated methylene species. Under mild reaction conditions (RT to 40 C), Cu(OTf)2 mediates the selective coupling of functionalized aryl boron species with a variety of stabilized sp3-nucl
New efficient ligand-free, copper nanoparticle catalyzed coupling reactions of aryl halides with diethyl malonate to produce α-arylation of malonates
Pai, Gita,Chattopadhyay, Asoke P.
, p. 1475 - 1482 (2013/06/27)
Recently synthesized copper nanoparticles (Cu NP) were used to catalyze coupling of aryl halides with diethyl malonates to produce α-aryl malonates. Synthetic conditions, including solvents, relative amounts of reactants, catalyst, and temperature, etc. h
