Copper-catalysed asymmetric allylic alkylation of alkylzirconocenes to racemic 3,6-dihydro-2H-pyrans

Beilstein Journal of Organic Chemistry

Emeline Rideau¹  Stephen P. Fletcher¹ 

[1] Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK, Fax: [phone];

关键词: allylic alkylation;    asymmetric catalysis;    copper;    design of experiments;    dynamic kinetic asymmetric transformation;    heterocycles;    Schwartz reagent;   

DOI  :  10.3762/bjoc.11.264

来源: DOAJ

【 摘 要 】

Asymmetric allylic alkylation is a powerful reaction that allows the enantioselective formation of C–C bonds. Here we describe the asymmetric alkylation of alkylzirconium species to racemic 3,6-dihydro-2H-pyrans. Two systems were examined: 3-chloro-3,6-dihydro-2H-pyran using linear optimization (45–93% ee, up to 33% yield, 5 examples) and 3,6-dihydro-2H-pyran-3-yl diethyl phosphate with the assistance of a design of experiments statistical approach (83% ee, 12% yield). 1H NMR spectroscopy was used to gain insight into the reaction mechanisms.

【 授权许可】

Unknown