Supported Gold Nanoparticle-Catalyzed Hydration of Alkynes under Basic Conditions
摘要:
TiO2-supported nanosize gold particles catalyze the hydration of alkynes using morpholine as a basic cocatalyst. Unlike most homogeneous cationic gold catalysts, the TiO2-Au/morpholine system is weakly basic and is compatible with acid-sensitive functional groups (e.g., silyl ethers, ketals) or with a strongly coordinating group such as pyridine. Whats more, this gold catalyst can be recycled by simple filtration and works well in flow reactors.
Water-soluble cobalt(III) porphyrin complexes were found to promote the hydration of terminal alkynes to give methyl ketones. The alkynehydration proceeded in good to excellent yield with 0.1 to 2 mol % cobaltcatalyst 1 and was compatible with the presence of acid/base- or redox-sensitive functional groups such as alkyl silyl ethers; allyl ethers; trityl ethers; benzyl ethers; carboxylic esters;
Cobaloxime-catalyzed hydration of terminal alkynes without acidic promoters
作者:Shengtai Hou、Hongjian Yang、Bin Cheng、Hongbin Zhai、Yun Li
DOI:10.1039/c7cc03919k
日期:——
Cobaloxime (Co(dmgBF2)2·2H2O), an inexpensive first-row transition-metal complex, catalyzedhydration of terminalalkynes gave the corresponding methyl ketones in good to excellent yields under neutral conditions (additional protic acids and silver salts are not required). A wide range of functional groups, such as allyl ether, benzyl ethers, carboxylic esters, imides, amides, nitro, and halogens,
an efficient synthesis of α‐fluoroketones by insertion of hydrogen fluoride (HF) into the gold carbene intermediate, generated from a cationicgold catalyzed addition of N‐oxides to alkynes. This method results in excellent chemical yields for a wide range of alkyne substrates and demonstrates good functional‐group tolerance.
Gold-Catalyzed Intermolecular Oxidation of Terminal Alkynes: Simple and Efficient Synthesis of α-Mesyloxy Ketones
作者:Weimin He、Jiannan Xiang、Longyong Xie、Zhiwu Liang、Dong Yan
DOI:10.1055/s-0033-1339337
日期:——
A variety of terminal alkynes were efficiently converted into the corresponding α-mesyloxy ketones through gold-catalyzedintermolecular oxidation in the presence of 3,5-dichloropyridine N-oxide as the oxidant. The reaction is proposed to proceed via α-oxo gold carbene intermolecular O–H insertion.