Palladium-Catalyzed Intramolecular Hydroalkylation of Alkenyl- ?-Keto Esters, ?-Aryl Ketones, and Alkyl Ketones in the Presence of Me3SiCl or HCl
作者:Xiaoqing Han、Xiang Wang、Tao Pei、Ross A. Widenhoefer
DOI:10.1002/chem.200400459
日期:2004.12.17
palladium-catalyzed hydroalkylation, but rather served as a source of HCl, which presumably catalyzes enolization of the ketone. Identification of HCl as the active promoter of palladium-catalyzed hydroalkylation led to the development of an effective protocol for the hydroalkylation of alkyl 3-butenyl ketones that employed sub-stoichiometric amounts of 2, HCl, and CuCl2 in a sealed tube at 70 degrees C.
Bromoetherification of Alkenyl Alcohols by Aerobic Oxidation of Bromide: Asymmetric Synthesis of 2‐Bromomethyl 5‐Substituted Tetrahydrofurans
作者:Akihiko Tomizuka、Katsuhiko Moriyama
DOI:10.1002/adsc.201801557
日期:2019.3.15
An asymmetricsynthesis of 2‐bromomethyl‐5‐substituted tetrahydrofurans via a chiral‐ruthenium‐catalyzed transfer hydrogenation of 3‐butenyl ketones and bromoetherification of chiral pentenyl alcohols was developed. The inhibition of some side reactions furnished the desired products in high yields with high enantioselectivities. In addition, chiral pentenyl alcohols bearing electron‐donating groups
The amino-Heck cyclization process has been applied into a range of gamma,delta-unsaturated ketone O-diethylphosphinyloximes 1 and delta,epsilon-unsaturated ketone O-diethylphosphinyloximes 7. Under the specific catalytic conditions developed by us, these substrates were found to preferentially undergo the 6-endo cyclization to give the formation of 2-substituted pyridines 3 and substituted methylpyridines 8, respectively, in moderate to good yields. Besides, several interesting aspects on the effects of phosphinyl groups, solvents, bases and molecular sieves on the regioselectivity of the cyclization of 1 have also been realized.
Pb(OAc)4-Cu(OAc)2-mediated oxidation of 1-alkylcyclohexanols; ?-decomposition of 1-alkylcycloalkoxy radicals