Gold-Catalyzed Hydrophenoxylation of Propargylic Alcohols and Amines: Synthesis of Phenyl Enol Ethers
作者:Victor Laserna、Catherine Jeapes Rojas、Tom D. Sheppard
DOI:10.1021/acs.orglett.9b01208
日期:2019.6.21
A practical method for the synthesis of phenyl enol ethers is reported. The combination of a gold(I) catalyst and potassium carbonate selectively mediates the addition of phenols to propargylic alcohols/amines in a chemo-, regio-, and stereoselective fashion in high yield. The resulting enol ethers are formed exclusively with a Z-configuration and can be obtained from a wide array of phenols and propargylic
Stereoselective Preparation of Acyclic<i>syn</i>-β-Amino Alcohols from β-Hydroxy Ketones via the Corresponding<i>O</i>-Benzyl Oximes
作者:Koichi Narasaka、Yutaka Ukaji、Shigeru Yamazaki
DOI:10.1246/bcsj.59.525
日期:1986.2
β-hydroxy ketone O-benzyl oximes with lithium aluminum hydride in the presence of sodium or potassium methoxide afforded the corresponding syn-β-amino alcohols in highly stereoselective manner. A lythraceae alkaloid, lasubine II, was synthesized stereoselectively by applying this method.
Stereoselective reduction of β hydroxyketones to 1,3-diols highly selective 1,3-asymmetric induction via boron chelates
作者:Koichi Narasaka、Fong-Chang Pai
DOI:10.1016/0040-4020(84)80006-x
日期:1984.1
Highly selective asymmetric induction can be achieved in the reduction of acyclic β-hydroxyketones via boron chelates. Treatment of β-hydroxyketones (1) with tributyl or tri-isobutylborane and successively with sodium borohydride afforded syn-1,3-diols (3) in highly stereo-selective manner, Syn -α-substituted-β -hydroxyketones (8) were also reduced to give syn, syn-1,3-diols (9) exclusively. The reaction
the reduction of nonconjugated Δ²-isoxazolines to the corresponding β-hydroxy ketones using Al/CuCl2 as the reducing agent has been developed. The method is both rapid and complete requiring less than ten minutes to attain total ring cleavage. This is the first example of using an in situ prepared Al/Cu couple in organic synthesis. reduction - isoxazolines - β-hydroxyketones - aluminum/copper couple
Hydroxyketones and diketones have been reduced with lithium indium hydride to give meso-diols selectively. α-Hydroxyketones and α-diketones are reduced to meso-1,2-diols with high diastereoselectivities, whereas the selectivities of β-hydroxyketones and β-diketones are less satisfactory.