functionality has been reliably transferred into nucleophilic radicals with the loss of one molecule of formaldehyde. Intriguingly, we found that the dehydroxymethylation process can be significantly promoted by the cerium catalyst, and the stabilization effect of the fragmented radicals also plays a significant role. This operationally simple protocol has enabled the direct utilization of primary alcohols as unconventional
Hypervalent iodine(III) catalyzed radical hydroacylation of chiral alkylidenemalonates with aliphatic aldehydes under photolysis
作者:Sermadurai Selvakumar、Qi-Kai Kang、Natarajan Arumugam、Abdulrahman I. Almansour、Raju Suresh Kumar、Keiji Maruoka
DOI:10.1016/j.tet.2017.08.018
日期:2017.10
bearing (−)-8-phenylmenthol as a chiral auxiliary with aliphaticaldehydes is realized under photolysis. This work represent the first example of diastereoselective addition of acyl radicals to olefins to afford chiral ketones in a highly stereoselective fashion. The reaction is initiated by the photolysis of hypervalent iodine(III) catalyst under mild and metal-free conditions. The synthetic potential
Enantioselective Friedel−Crafts Alkylation of Indoles with Trifluoroethylidene Malonates by Copper−Bis(oxazoline) Complexes: Construction of Trifluoromethyl-Substituted Stereogenic Tertiary Carbon Center
作者:Lele Wen、Qilong Shen、Xiaolong Wan、Long Lu
DOI:10.1021/jo1024333
日期:2011.4.1
An enantioselective alkylation of indoles with trifluoroethylidene malonates catalyzed by copper(II)−bis (oxazoline) complexes has been developed. The expected adducts with a stereogenic tertiary carboncenter bearing a trifluoromethyl group were obtained in excellent yields (up to 99%) and ee values (up to 96% ee). The synthetic utility of this asymmetric catalytic reaction was demonstrated by the
Diastereoselective radical hydroacylation of chiral alkylidenemalonates with aliphatic aldehydes is realized by the combination of a hypervalentiodine(III) reagent and UV‐light irradiation. The reaction is initiated by the photolysis of hypervalentiodine(III) reagents under mild, metal‐free conditions, and is the first example of diastereoselective addition of acyl radicals to olefins to afford chiral
Enantioselective Organocatalytic Michael Addition of Aldehydes to Trifluoroethylidene Malonates
作者:Lele Wen、Qilong Shen、Long Lu
DOI:10.1021/ol101894h
日期:2010.10.15
An efficient, highly enantioselective, organocatalyticMichaeladdition reaction of aldehydes with trifluoroethylidene malonates is described. The asymmetric reaction provided highly optically pure β-trifluoromethyl aldehydes which can be conveniently transformed into 4,4,4-trifluoromethyl butyric acid and trifluoromethyl substituted δ-lactones without loss in enantioselectivity.