The acid free asymmetric intermolecular α-alkylation of aldehydes in fluorinated alcohols
作者:Jian Xiao、Kai Zhao、Teck-Peng Loh
DOI:10.1039/c2cc30261f
日期:——
The acid free asymmetric intermolecular α-alkylation of aldehydes with alcohols has been discovered using trifluoroethanol as solvent. This unprecedented system affords the enantioenriched functionalized primary alcohols (after NaBH4 reduction) in high yields and good to excellent enantioselectivities with wide substrate scope in the absence of any acid additive.
An organocatalytic enantioselective intermolecular oxidative dehydrogenative α-alkylation of aldehydes via benzylic C–H bond activation has been developed. The asymmetric reaction is smoothly fulfilled by using simple and green molecular oxygen as the oxidant. Two hydrogen dissociations make this transformation more environmentally benign because of high atom efficiency.
Highly Enantioselective Intermolecular Alkylation of Aldehydes with Alcohols by Cooperative Catalysis of Diarylprolinol Silyl Ether with Brønsted Acid
作者:Jian Xiao、Kai Zhao、Teck-Peng Loh
DOI:10.1002/asia.201100692
日期:2011.11.4
Two cooperative systems: I/2,3,4‐trihydroxybenzoic acid and I/TfOH effect highlyenantioselective intermolecular α‐alkylation of aldehydes. These systems afford functionalized aldehydes in high yields, and with excellent ee and de values with broad substrate scope (see scheme; R1=alkyl, R2,R3=aryl, or R2=ferrocenyl, R3=phenyl, or R2=indolyl, R3=phenyl).