7780-06-5Relevant articles and documents
Multiple-Functional Diphosphines: Synthesis, Characterization, and Application to Pd-Catalyzed Alkoxycarbonylation of Alkynes
Chen, Xiao-Chao,Guo, Lin,Liu, Lei,Liu, Ye,Lu, Yong,Yao, Yin-Qing,Zhao, Kai-Chun,Zhao, Xiao-Li
, p. 750 - 760 (2022/04/03)
A series of diphosphine ligands (L1-L5) containing bis-phosphino fragments and bis-amido groups as well as intensive electron-withdrawing F atoms were synthesized and fully characterized. The structures of the prepared complex of Pd-L5 demonstrate that as for L5, the incorporated two phosphino fragments participate in the chelation to the Pd center inversely along with two Cl-ligands to present a typical square-planar configuration, whereas the two amido groups simultaneously develop a hydrogen-bond interaction with Cl-ligands to facilitate the timely dissociation of Cl-ligands from the Pd center. It was found that L5 enabled the Pd complex to be more active in the alkoxycarbonylation of alkynes with MeOH for the synthesis of branched/linear α,β-unsaturated carboxylic esters with general yields of 60-89%. In L5, the incorporated diphosphino fragments, diamino groups, and F atoms conferred a catalytic effect to the Pd complex synergetic toward the reaction.
An ionic liquid catalyzed probase method for one-pot synthesis of α,β-unsaturated esters from esters and aldehydes under mild conditions
Wang, Gang,Xu, Yiming,Zhang, Suojiang,Li, Zengxi,Li, Chunshan
, p. 4838 - 4848 (2017/10/23)
A one-pot synthesis of α,β-unsaturated esters from unactivated esters and aldehydes using strong bases, such as sodium alkoxide and potassium tert-butoxide, was reported. However, the ionic liquid (IL) catalyzed probase method for producing α,β-unsaturated esters was not reported until now. In this work, a series of ILs with fluoride anions were firstly prepared and used as catalysts in combination with the probase N,O-bis(trimethylsilyl) acetamide (BSA) for the α,β-unsaturated esters synthesis. This process could also be promoted through the introduction of another IL with Lewis acid sites. The yield and selectivity of the product could reach up to 84.2% and 95.0%, respectively, when [Bmim]F was used in combination with [Bmim]Cl/AlCl3 (the molar fraction of AlCl3 is 0.67). The mechanism investigation through GC-MS indicates that BSA would convert into onium amide, which acted as a strong base for α-H abstraction, with the catalysis of [Bmim]F. Meanwhile, [Bmim]Cl/AlCl3 played an important role in the condensation step between enolates and aldehydes. On the basis of mechanism insights, kinetic and thermodynamic studies were also carried out for a better understanding of this new route.
Borane-Catalyzed Reductive α-Silylation of Conjugated Esters and Amides Leaving Carbonyl Groups Intact
Kim, Youngchan,Chang, Sukbok
supporting information, p. 218 - 222 (2016/01/25)
Described herein is the development of the B(C6F5)3-catalyzed hydrosilylation of α,β-unsaturated esters and amides to afford synthetically valuable α-silyl carbonyl products. The α-silylation occurs chemoselectively, thus leaving the labile carbonyl groups intact. The reaction features a broad scope of both acyclic and cyclic substrates, and the synthetic utility of the obtained α-silyl carbonyl products is also demonstrated. Mechanistic studies revealed two operative steps: fast 1,4-hydrosilylation of conjugated carbonyls and then slow silyl group migration of a silyl ether intermediate.