conversion of prochiral tert‐cyclobutanols to β‐methyl‐substituted ketones proceeds under comparably mild conditions in toluene (45–110 °C) and is particularly suited for the enantioselective desymmetrization of β‐oxy‐substituted substrates to give products with a quaternary chirality center with up to 95 % ee using DTBM‐SegPhos as a chiral ligand. Deuteration experiments and kinetic isotope effect measurements
Double Asymmetric Hydrogenation of Linear β,β-Disubstituted α,β-Unsaturated Ketones into γ-Substituted Secondary Alcohols using a Dual Catalytic System
β‐unsaturated ketones catalyzed by the DM‐SEGPHOS/DMAPEN/RuII complex with t‐C4H9OK afforded the γ‐substituted secondaryalcohols in high diastereo‐ and enantioselectivities. Some mechanistic experiments suggested that two different reactive species, type (I) and (II), were reversibly formed in this catalytic system: Type (I) with the diamine ligand DMAPEN enantioselectively hydrogenated the enones
Making Mixtures to Solve Structures: Structural Elucidation via Combinatorial Synthesis
作者:Nigel A. Lengkeek、Paul F. Greenwood、Blake Nguyen、George A. Koutsantonis、Matthew J. Piggott
DOI:10.1021/cc900134t
日期:2010.1.11
A domino Horner-Wadsworth-Emmons olefination strategy has been used to prepare homologous series of (polyen)ones, and through combinatorial elaboration, corresponding families of highly branched hydrocarbons. Gas chromatography-mass spectrometry of the mixtures has enabled the rapid and unambiguous identification of several highly branched alkanes of geochemical importance. This is the first example of the use of combinatorial synthesis for the elucidation of structural connectivity.
Photochemical reaction of trialkylboranes and β-dicarbonyl compounds
作者:Kiitiro Utimoto、Toshio Tanaka、Hitosi Nozaki
DOI:10.1016/s0040-4039(01)84536-6
日期:1972.1
Novel photochemical alkyl migrations of dialkylboryl acetylacetonate complexes