- Asymmetric Friedel-Crafts alkylation of methoxyfuran with nitroalkenes catalyzed by diphenylamine-tethered bis(oxazoline)-Zn(II) complexes.
Asymmetric Friedel-Crafts alkylation of methoxyfuran with nitroalkenes catalyzed by diphenylamine-tethered bis(oxazoline)-Zn(II) complexes.
Organic letters (2007-10-11)
Han Liu, Jiaxi Xu, Da-Ming Du
PMID17924637
ABSTRACT
The first catalytic asymmetric Friedel-Crafts reaction of 2-methoxyfuran with nitroalkenes was developed under the catalysis of diphenylamine-tethered bis(oxazoline)-Zn(OTf)2 complexes. The reaction conditions and ligands were optimized, and the scope of the reaction was tested by varying the nitroalkenes. For most of aromatic and heteroaromatic nitroalkenes, good yields and high enantioselectivities (86-96% ee) were obtained. The methoxyfuran group in the product can be transformed to carboxylic acid via oxidative fragmentation with full retention of the configuration.
MATERIALS