Catalytic Enantioselective [2 + 4] and [2 + 2] Cycloaddition Reactions with Propiolamides
摘要:
We report here the catalytic and highly enantioselective [2 + 4] and [2 + 2] cycloaddition reactions of electron-rich dienes or silyl enol ethers with electron-deficient propiolamide derivatives induced by copper(II)center dot 3-(2-naphthyl)-L-alanine amide complex.
A Bioinspired Cyclization Sequence Enables the Asymmetric Total Synthesis of Dictyoxetane
作者:Cedric L. Hugelshofer、Thomas Magauer
DOI:10.1021/jacs.6b03720
日期:2016.5.25
developed the first synthesis of the unique oxetane containing diterpene (+)-dictyoxetane. Our retrosynthetic planning was guided by the putative biosynthesis of the unprecedented 2,7-dioxatricyclo[4.2.1.0(3,8)]nonane ring system. A bioinspired 4-exo-tet, 5-exo-trig cyclization sequence enabled the construction of the synthetically challenging dioxatricyclic framework. The overall synthesis proceeds in 15
A Divergent Approach to the Marine Diterpenoids (+)-Dictyoxetane and (+)-Dolabellane V
作者:Cedric L. Hugelshofer、Thomas Magauer
DOI:10.1002/chem.201603061
日期:2016.10.10
addition reactions to assemble the full carbon skeleton, a Grobfragmentation to construct the 11‐membered macrocycle of (+)‐dolabellane V, and a bioinspired 4‐exo‐tet, 5‐exo‐trig cyclization sequence to form the complex dioxatricyclic framework of (+)‐dictyoxetane. Furthermore, an unprecedented strain‐releasing type I dyotropic rearrangement of an epoxide‐oxetane substrate was developed.
Enantioselective Synthesis of Homologous Methyl-Substituted Bicyclic Enones Through Michael-Type Alkylation of Chiral Imines
作者:Virginie Goubaud、Robert Azerad
DOI:10.1080/00397919608003696
日期:1996.3
Abstract The preparation of 4a-methyl-substituted bicyclic enones in high enantiomeric purity is described, involving a Michael alkylation of (R)- or (S)-1-phenylethyl imines of the corresponding (±)-2-methylcyclopentanone, 2-methyl-cyclohexanone, 2-methylcycloheptanone, and 2-methylcyclooctanone with methyl vinyl ketone.
The regio- and stereoselective hydroxylation of enantiomeric 4a-methyl hydrindenones by selected fungal strains has been shown to afford several enantiomerically pure derivatives, hydroxylated in the B-ring. The potential of this method for the preparation of hydroxylated chiral synthons is evaluated and discussed.
Catalytic Enantioselective [2 + 4] and [2 + 2] Cycloaddition Reactions with Propiolamides
作者:Kazuaki Ishihara、Makoto Fushimi
DOI:10.1021/ja8015318
日期:2008.6.18
We report here the catalytic and highly enantioselective [2 + 4] and [2 + 2] cycloaddition reactions of electron-rich dienes or silyl enol ethers with electron-deficient propiolamide derivatives induced by copper(II)center dot 3-(2-naphthyl)-L-alanine amide complex.