Origin of Chiral Induction in Radical Reactions with the Diastereoisomers (5R)- and (5S)-5-l-Menthyloxyfuran-2[5H]-one
摘要:
Acetalization of 5-hydroxyfuran-2[5H]-one with l-menthol yields (5R)-(1) and (5S)-5-l-menthyloxyfuran-2[5H]-one (2) in equal amounts. The diastereomer 1 crystallizes preferentially. For the first time, the isolation of pure diastereoisomer 2 is reported. Different diastereoselectivities were observed in the radical tandem reaction of 1 and 2 with N,N-dimethylaniline. The privileged conformations in solution of the substrates and the products of the radical reaction were then determined, and X-ray crystal structure analyses were carried out on the reaction products. The different stereoselectivities in both cases are explained by different orientations of the menthyloxy substituent.
Visible-light-induced, Ir-catalyzed reactions of <i>N</i>-methyl-<i>N</i>-((trimethylsilyl)methyl)aniline with cyclic α,β-unsaturated carbonyl compounds
作者:Dominik Lenhart、Thorsten Bach
DOI:10.3762/bjoc.10.86
日期:——
reagent in visible-light-induced, iridium-catalyzed addition reactions to cyclicalpha,beta-unsaturated carbonyl compounds. Typical reaction conditions included the use of one equivalent of the reaction substrate, 1.5 equivalents of the aniline and 2.5 mol % (in MeOH) or 1.0 mol % (in CH2Cl2) [Ir(ppy)2(dtbbpy)]BF4 as the catalyst. Two major reaction products were obtained in combined yields of 30-67%. One