1036645-45-0Relevant articles and documents
Highly enantioselective addition of arylzinc reagents to aldehydes promoted by chiral aziridine alcohols
Wujkowska, Zuzanna,Jarzyński, Szymon,Pieczonka, Adam M.,Le?niak, Stanis?aw,Rachwalski, Micha?
, p. 1238 - 1244 (2016/11/23)
Enantiomerically pure, chiral secondary and tertiary aziridine alcohols have proven to be highly efficient catalysts for enantioselective asymmetric additions of arylzinc species to aldehydes leading to products in high chemical yields (up to 90%) and with ee's up to 90%. The influence of the stereogenic centers located at the aziridine subunit on the stereochemical course of the reaction is discussed.
Aryl bromides as inexpensive starting materials in the catalytic enantioselective arylation of aryl aldehydes: The additive TMEDA enhances the enantioselectivity
Yang, Yong-Xin,Liu, Yue,Zhang, Lei,Jia, Yan-E,Wang, Pei,Zhuo, Fang-Fang,An, Xian-Tao,Da, Chao-Shan
, p. 10696 - 10702 (2015/02/19)
We used aryl bromides as inexpensive starting materials to enantioselectively arylate aldehydes in one pot. Aryl bromides readily transfer aryls to aryllithiums with n-butyllithium, successively to triarylaluminums with aluminum chloride, and then to aryltitaniums with titanium isopropoxide. Finally aryltitaniums arylate aldehydes catalyzed by (S)-H8-BINOL-Ti(Oi-Pr)2 in excellent yields and enantioselectivities. The additive TMEDA evidently suppresses the racemic background reaction promoted by LiCl generated from salt metathesis. This procedure represents a cost-effective and operationally convenient method for enantioenriched diarylmethanols.
Facile synthesis of a family of H8BINOL-amine compounds and catalytic asymmetric arylzinc addition to aldehydes
Deberardinis, Albert M.,Turlington, Mark,Ko, Jason,Sole, Laura,Pu, Lin
supporting information; experimental part, p. 2836 - 2850 (2010/08/05)
A family of optically active H8BINOL-AM compounds containing 3,3′-bis-tertiary amine substituents are synthesized by using a one-step reaction of H8BINOL with amino methanols that were in situ generated from various cyclic or acyclic secondary amines and paraformaldehyde. The H 8BINOL-AM compounds are used to catalyze the reaction of functional arylzincs, in situ prepared from the reaction of aryliodides with ZnEt 2, with aldehydes to produce chiral diaryl carbinols and a few arylalkyl carbinols. Through this study, highly enantioselective catalysts were identified. It was found that the H8BINOL-AM compounds with sterically less congested cyclic or acyclic amino methyl substituents were more enantioselective than those with more bulky substituents. The pyrrolidinyl derivative (S)-12 in most cases showed greater enantioselectivity than other H8BINOL-AM compounds, especially for the challenging ortho-substituted aromatic aldehydes. A H8BINOL-AM with 3,3′-bis-sec-amine substituents, prepared by a multistep method, was also used to catalyze the arylzinc addition to aldehydes, but it showed enantioselectivity lower than that of the compounds with tertiary amine groups. It was found for the first time that an aryl bromide, 2-bromothiophene, could be used to prepare an arylzinc reagent by reaction with ZnEt2. The addition of this heteroarylzinc reagent to an aldehyde in the presence of (S)-12 proceeded with good enantioselectivity.
Activation of functional arylzincs prepared from aryl iodides and highly enantioselective addition to aldehydes
DeBerardinis, Albert M.,Turlington, Mark,Pu, Lin
supporting information; experimental part, p. 2709 - 2712 (2009/05/27)
(Chemical Equation Presented) An easily available chiral ligand (S)-1 is found to activate the nucleophilic reaction of the arylzincs prepared in situ from the reaction of aryl iodides with Et2Zn. Both high yields and high enantioselectivity (u
