Use of Conjugated Dienones in Cyclialkylations: Total Syntheses of Arucadiol, 1,2-Didehydromiltirone, (±)-Hinokione, (±)-Nimbidiol, Sageone, and Miltirone
摘要:
Functionalized hydrophenanthrenes can be prepared using a cyclialkylation-based strategy. These annulations are highly dependent on the directing effects of the arene substitutents and on conformational considerations. The utility of this methodology was featured in the syntheses of six diterpenoids.
Asymmetric Hydrogenation of α,α′-Disubstituted Cycloketones through Dynamic Kinetic Resolution: An Efficient Construction of Chiral Diols with Three Contiguous Stereocenters
Chiral diols with threecontiguousstereocenters were synthesized by a highly enantioselective ruthenium‐catalyzedasymmetric hydrogenation of racemic α,α′‐disubstituted cycloketones involving dynamic kineticresolution. This new catalytic asymmetric method provides a concise route to the alkaloid (+)‐γ‐lycorane.
Dynamic Kinetic Resolution of γ-Substituted Cyclic β-Ketoesters via Asymmetric Hydrogenation: Constructing Chiral Cyclic β-Hydroxyesters with Three Contiguous Stereocenters
An efficient asymmetric hydrogenation of racemic γ-substituted cyclic β-ketoesters via dynamic kineticresolution to provide chiral cyclic β-hydroxy esters with threecontiguousstereocenters is reported. Using a chiral spiro iridium catalyst (R)-5 (Ir-SpiroSAP), a series of racemic γ-aryl/alkyl substituted cyclic β-ketoesters were hydrogenated to the corresponding chiral cyclic β-hydroxy esters in
Use of Conjugated Dienones in Cyclialkylations: Total Syntheses of Arucadiol, 1,2-Didehydromiltirone, (±)-Hinokione, (±)-Nimbidiol, Sageone, and Miltirone
Functionalized hydrophenanthrenes can be prepared using a cyclialkylation-based strategy. These annulations are highly dependent on the directing effects of the arene substitutents and on conformational considerations. The utility of this methodology was featured in the syntheses of six diterpenoids.
Asymmetric Hydrogenation of Racemic 6-Aryl 1,4-Dioxaspiro[4.5]decan-7-ones to Functionalized Chiral β-Aryl Cyclohexanols via a Dynamic Kinetic Resolution
asymmetric hydrogenation method for the synthesis of functionalized β-aryl cyclohexanols is described. With chiral spiro ruthenium catalyst (Ra,S,S)-5c, a series of racemic α-aryl cyclohexanones bearing a β-monoethylene ketal group were hydrogenated to the corresponding functionalized β-aryl cyclohexanols in high yields with enantioselectivity of up to 99% ee via a dynamic kinetic resolution. This protocol