Synthetic methods and reactions. 123. Preparation of .alpha.-chloro ketones from enol silyl ethers with sulfuryl chloride fluoride and sulfuryl chloride
A novel palladium-catalyzed preparative method of α,β-unsaturated ketones and aldehydes from saturated ketones and aldehydes via their silyl enol ethers
作者:Jiro Tsuji、Ichiro Minami、Isao Shimizu
DOI:10.1016/s0040-4039(00)94160-1
日期:1983.1
Silyl enol ethers prepared from saturated ketones and aldehydes can be converted to α,β-unsaturated ketones and aldehydes by the reaction of allyl carbonate in the presence of palladium-phosphine complexes as a catalyst. The selection of solvent is crucial and nitriles are most effective as the solvent.
A new, practical route to enoxysilanes is described from simple enolizable aldehydes or ketones, using the trimethylchlorosilane-sodium iodide—tertiary amine reagent in acetonitrile. From certain aldehydes, an onium intermediate has been isolated. A conformational study of this onium intermediate and a thermal unimolecular syn-elimination process may explain the stereoselectivity of the reaction. Such
New synthetic methods for α,β -unsaturated ketones, aldehydes, esters and lactones by the palladium-catalyzed reactions of silyl enol ethers, ketene silyl acetals, and enol acetates with allyl carbonates
Silyl enol ethers and ketenesilylacetals derived from ketones, aldehydes, esters and lactones are converted into α,β-unsaturated ketones, aldehydes, esters and lactones by treatment with allyl carbonates in high yields using the palladium—bis(diphenylphosphino)ethane (dppe) complex as catalyst. Phosphine-free palladium catalyst instead of the palladium—phosphine complex gives a higher selectivity
Treatment of aliphatic carbonylcompounds with trimethylsilyl chloride with Mg turning for Grignard reaction without any pre-treatment in N,N-dimethylformamide at room temperature brought about highly facile, effective and stereoselective coupling to give the corresponding silylenolethers in good yields.