72902-79-5Relevant academic research and scientific papers
Highly enantioselective addition of dimethylzinc to arylaldehydes catalyzed by (2S)-1-ferrocenyl-methylaziridin-2-yl(diphenyl)methanol
Wang, Min-Can,Zhang, Qing-Jian,Li, Gao-Wei,Liu, Zhi-Kang
experimental part, p. 288 - 292 (2009/09/05)
Asymmetric addition of dimethylzinc to a wide variety of aromatic aldehydes is described in the presence of a catalytic amount of chiral β-amino alcohol [(2S)-1-ferrocenyl- methylaziridin-2-yl(diphenyl)methanol], and a reaction enantioselectivity of up to 97.5% ee was achieved in this transformation in the absence of additional metals such as Ti or Ni. The results showed that this particular addition reaction, characterized by the lower reactivity of dimethylzinc with aldehydes, was more sensitive to structural variations in substrate aldehydes than the corresponding diethylzinc addition. A possible transition state for the catalytic asymmetric addition has been proposed on the basis of previous studies.
Evaluation of enantiopure N-(ferrocenylmethyl)azetidin-2-yl(diphenyl) methanol for catalytic asymmetric addition of organozinc reagents to aldehydes
Wang, Min-Can,Zhang, Qing-Jian,Zhao, Wen-Xian,Wang, Xiao-Dan,Ding, Xue,Jing, Tao-Tao,Song, Mao-Ping
, p. 168 - 176 (2008/09/17)
(Chemical Equation Presented) A facile and practical approach to preparation of enantiopure N-(ferrocenylmethyl)azetidin-2-yl(diphenyl)-methanol was developed from cheap and easily available L-(+)-methionine. Synthetic highlights include the three-step, one-pot construction of the chiral azetidine ring and the development of an improved one-step procedure for the synthesis of the key intermediate L-2-amino-4-bromobutanoic acid. Enantiopure N-(ferrocenylmethyl)azetidin-2-yl(diphenyl)methanol was evaluated for catalytic asymmetric addition of organozinc reagents to aldehydes. The asymmetric ethylation, methylation, arylation, and alkynylation of aldehydes achieved enantioselectivity of up to 98.4%, 94.1%, 99.0%, and 84,6% ee, respectively, in the presence of a catalytic amount of chiral N-(ferrocenylmethyl)azetidin-2- yl(diphenyl)methanol. Our results demonstrated further that the four-membered heterocycle-based backbone was a good potential chiral unit for the catalytic asymmetric induction reaction, and the hindrance of the bulky ferrocenyl group, compared to a phenyl group, played an important role in the enantioselectivities. A possible transition for the catalytic asymmetric addition has been proposed on the basis of the crystal structure of the chiral ligand 3b including two HOAc molecules and previous studies.
ASYMMETRIC SYNTHESIS via CHIRAL ACETAL TEMPLATES. 8. REACTIONS WITH ORGANOMETALLIC REAGENTS
Lindell, Stephen D.,Elliott, John D.,Johnson, William S.
, p. 3947 - 3950 (2007/10/02)
The titanium tetrachloride catalyzed coupling of organometallic reagents with chiral acetals 1 is shown to provide a convenient route for the preparation of a variety of chiral alcohols 4 of high optical purity.
