Evaluation of Enantiopure N-(Ferrocenylmethyl)azetidin-2-yl(diphenyl)methanol for Catalytic Asymmetric Addition of Organozinc Reagents to Aldehydes
| Autor: | Xue Ding, Qing-Jian Zhang, Min-Can Wang, Mao-Ping Song, Wen-Xian Zhao, Tao-Tao Jing, Xiao-Dan Wang |
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| Rok vydání: | 2007 |
| Předmět: |
chemistry.chemical_classification
Organic Chemistry Azetidine Molecular Conformation Enantioselective synthesis Stereoisomerism Ligands Combinatorial chemistry Chemical synthesis Aldehyde Asymmetric induction Catalysis chemistry.chemical_compound Enantiopure drug chemistry Alcohols Benzaldehydes Organometallic Compounds Organic chemistry Ferrous Compounds Enantiomeric excess |
| Zdroj: | The Journal of Organic Chemistry. 73:168-176 |
| ISSN: | 1520-6904 0022-3263 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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