Reagent-controlled enantioselectivity switch for the asymmetric fluorination of β-ketocarbonyls by chiral primary amine catalysis
作者:Yang'en You、Long Zhang、Sanzhong Luo
DOI:10.1039/c6sc03109a
日期:——
enantioselectivity switch was uncovered in the asymmetric α-fluorination of β-ketocarbonyls by a chiral primary amine catalyst. By a simple swap of fluorination reagents, both enantiomers of the quaternary fluorination adducts could be obtained with good yields and high enantioselectivity. Mechanistic studies disclosed dual H-bonding and electrostatic stereocontrolling modes for the catalysis.
Chiral Primary Amine/Ketone Cooperative Catalysis for Asymmetric α-Hydroxylation with Hydrogen Peroxide
作者:Mao Cai、Kaini Xu、Yuze Li、Zongxiu Nie、Long Zhang、Sanzhong Luo
DOI:10.1021/jacs.0c11787
日期:2021.1.20
catalytic strategies, aminocatalysis and carbonyl catalysis do not coexist well, and, as such, a cooperative amine/carbonyl dual catalysis remains essentially unknown. Here we report a cooperative primary amine and ketone dual catalytic approach for the asymmetric α-hydroxylation of β-ketocarbonyls with H2O2. Besides participating in the typical enamine catalytic cycle, the chiral primary amine catalyst
Synthesis of 3-Carbonyl Trisubstituted Furans via Pd-Catalyzed Aerobic Cycloisomerization Reaction: Development and Mechanistic Studies
作者:Amanda A. Barboza、Attilio Chiavegatti Neto、Isac G. Rosset、Guilherme A. M. Jardim、Marco A. B. Ferreira
DOI:10.1021/acs.joc.0c02777
日期:2021.3.5
we report the synthesis of 3-carbonyl-trisubstituted furans via Pd-catalyzed oxidative cycloisomerization reactions of 2-alkenyl-1,3-dicarbonyl scaffolds, using molecular oxygen as the sole oxidant to regenerate active palladium catalytic species, featuring good functional tolerance and mild reaction conditions. Deep investigation of intermediates and transition states of the reaction mechanism were
Catalytic Asymmetric Mannich Reaction with N-Carbamoyl Imine Surrogates of Formaldehyde and Glyoxylate
作者:Yang'en You、Long Zhang、Linfeng Cui、Xueling Mi、Sanzhong Luo
DOI:10.1002/anie.201707005
日期:2017.10.23
N,O‐acetals (NOAcs) were developed as bench stable surrogates for N‐carbamoyl, (Boc, Cbz and Fmoc) formaldehyde and glyoxylate imines in asymmetric Mannich reactions. The NOAcs can be directly utilized in the chiral primary amine catalyzed Mannich reactions of both acyclic and cyclic β‐ketocarbonyls with high yields and excellent stereoselectivity. The current reaction offers a straightforward approach
Hydrogen Peroxide or Peracetic Acid Mediated Self-Titrating α-Halogenation of 1,3-Dicarbonyl Compounds
作者:Hasim Ibrahim、Ramulu Akula、Marc Galligan
DOI:10.1055/s-0030-1258367
日期:2011.1
Efficient oxidative α-halogenation of 1,3-dicarbonylcompounds has been achieved by employing a system comprising of sub-stoichiometric amounts of TiX4 (X = Cl, Br) in conjunction with environmentally benign hydrogen peroxide (H2O2) or peracetic acid (MeCO3H) as the oxidants. The end point of the reaction is accompanied by a sharp colour change. halogenation - peroxides - titanium - halides - electrophilic
通过使用包含亚化学计量量的TiX 4(X = Cl,Br)以及环境友好的过氧化氢(H 2 O 2)或过氧乙酸的系统,可以实现1,3-二羰基化合物的有效氧化α-卤化酸(MeCO 3 H)作为氧化剂。反应的终点伴随着急剧的颜色变化。 卤化-过氧化物-钛-卤化物-亲电子