42393-11-3Relevant articles and documents
Asymmetric Catalytic Formal 1,4-Allylation of β,γ-Unsaturated α-Ketoesters: Allylboration/Oxy-Cope Rearrangement
Tang, Qiong,Fu, Kai,Ruan, Peiran,Dong, Shunxi,Su, Zhishan,Liu, Xiaohua,Feng, Xiaoming
, p. 11846 - 11851 (2019/07/19)
A highly enantioselective formal conjugate allyl addition of allylboronic acids to β,γ-unsaturated α-ketoesters has been realized by employing a chiral NiII/N,N′-dioxide complex as the catalyst. This transformation proceeds by an allylboration/oxy-Cope rearrangement sequence, providing a facile and rapid route to γ-allyl-α-ketoesters with moderate to good yields (65–92 %) and excellent ee values (90–99 % ee). The isolation of 1,2-allylboration products provided insight into the mechanism of the subsequent oxy-Cope rearrangement reaction: substrate-induced chiral transfer and a chiral Lewis acid accelerated process. Based on the experimental investigations and DFT calculations, a rare boatlike transition-state model is proposed as the origin of high chirality transfer during the oxy-Cope rearrangement.
Boosting Chemical Stability, Catalytic Activity, and Enantioselectivity of Metal-Organic Frameworks for Batch and Flow Reactions
Chen, Xu,Jiang, Hong,Hou, Bang,Gong, Wei,Liu, Yan,Cui, Yong
, p. 13476 - 13482 (2017/10/05)
A key challenge in heterogeneous catalysis is the design and synthesis of heterogeneous catalysts featuring high catalytic activity, selectivity, and recyclability. Here we demonstrate that high-performance heterogeneous asymmetric catalysts can be engineered from a metal-organic framework (MOF) platform by using a ligand design strategy. Three porous chiral MOFs with the framework formula [Mn2L(H2O)2] are prepared from enantiopure phosphono-carboxylate ligands of 1,1′-biphenol that are functionalized with 3,5-bis(trifluoromethyl)-, bismethyl-, and bisfluoro-phenyl substituents at the 3,3′-position. For the first time, we show that not only chemical stability but also catalytic activity and stereoselectivity of the MOFs can be tuned by modifying the ligand structures. Particularly, the MOF incorporated with -CF3 groups on the pore walls exhibits enhanced tolerance to water, weak acid, and base compared with the MOFs with -F and -Me groups. Under both batch and flow reaction systems, the CF3-containing MOF demonstrated excellent reactivity, selectivity, and recyclability, affording high yields and enantioselectivities for alkylations of indoles and pyrrole with a range of ketoesters or nitroalkenes. In contrast, the corresponding homogeneous catalysts gave low enantioselectivity in catalyzing the tested reactions.
Synthesis of functionalized 2,5-dihydro-1,2-oxaphospholes via one-pot three-component reaction
Balalaie, Saeed,Baoosi, Leila,Tahoori, Fatemeh,Rominger, Frank,Bijanzadeh, Hamid Reza
, p. 101 - 105 (2015/01/30)
An efficient one-pot synthesis of novel 2,5-dihydro-1,2-oxaphosphole derivatives via a three-component reaction of triphenyl phosphine, dialkyl acetylenedicarboxylates, and methyl (arylmethylidene) pyruvates has been reported. Carrying out the reaction in
