New Cross Aldol Reactions. Titanium Tetrachloride-promoted Reactions of Silyl Enol Ethers with Carbonyl Compounds Containing A Functional Group
作者:Kazuo Banno
DOI:10.1246/bcsj.49.2284
日期:1976.8
It was found that, in the presence of titanium tetrachloride, silylenolethersselectively react with aldehyde or ketone function of various carbonyl compounds containing another functional group giving the corresponding cross aldols in good yields. The present cross aldol reaction was successfully applied to the synthesis of arturmerone, one of the volatile principles of turmeric oil.
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
Stereoselective aryl migration reactionsfromsulfur in sulfonates and sulfonamides to C-centered radicals are reported. The 1,5-aryl migration fromsulfur to differently substituted C-centered radicals could be performed with high yields and selectivities. Functionalized aryl groups could also be transferred by this new method. A model to explain the stereochemical outcome of the reaction is presented and some