Dinuclear zinc complex catalyzed asymmetric methylation and alkynylation of aromatic aldehydes
| Autor: | Min-Can Wang, De-Yang Zhang, Shanshan Liu, Gao-Wei Li, Xiao-Chao Yang |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
010405 organic chemistry
Stereochemistry Organic Chemistry Dimethylzinc Chiral ligand Azetidine Enantioselective synthesis Substituent chemistry.chemical_element Zinc 010402 general chemistry 01 natural sciences Biochemistry Combinatorial chemistry 0104 chemical sciences Catalysis chemistry.chemical_compound chemistry Stereoselectivity Physical and Theoretical Chemistry |
| Zdroj: | Organicbiomolecular chemistry. 15(34) |
| ISSN: | 1477-0539 |
| Popis: | A general AzePhenol dinuclear zinc catalytic system has been successfully developed and introduced into the asymmetric addition of dimethylzinc and alkynylzinc to aromatic aldehydes. In this system, an azetidine derived chiral ligand has proven to be an effective enantioselective promoter. Under the optimal reaction conditions, a series of chiral 1-hydroxyethyl (up to 99% ee) and secondary propargylic alcohols (up to 96% ee) were generated with good yields and enantioselectivities. Additionally, this novel catalytic system showed good functional group compatibility. Remarkably, the substituent's electronic nature alone is not sufficient to allow for exclusive enantioselectivity, an additional substituent's location also had an effect. We proposed that the formation of a stable and structural rigid transition state by the chelation of ortho substituted benzaldehydes to the zinc atom was responsible for the observed higher enantioselectivity. The possible catalytic cycles of both transformations accounting for the stereoselectivity were described accordingly. |
| Databáze: | OpenAIRE |
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