Sustainable Synthesis of Oximes, Hydrazones, and Thiosemicarbazones under Mild Organocatalyzed Reaction Conditions
作者:Sara Morales、José Luis Aceña、José Luis García Ruano、M. Belén Cid
DOI:10.1021/acs.joc.6b01912
日期:2016.10.21
thiosemicarbazones derived from aromatic and aliphaticaldehydes using equimolar amounts of reagents and green solvents. Experimental simplicity and excellent yields after a simple filtration are the main advantages of the method, being an alternative to those currently available especially for the acyl derivatives, which do not work under uncatalyzed conditions. Its application to the synthesis of acyloximes by
Catalytic asymmetric aza Diels–Alder reactions of hydrazones using a chiral zirconium catalyst
作者:Yasuhiro Yamashita、Yumiko Mizuki、Shū Kobayashi
DOI:10.1016/j.tetlet.2005.01.111
日期:2005.3
Catalyticasymmetric aza Diels–Alderreactions of acylhydrazones with Danishefsky’s dienes have been developed. A chiral zirconium complex derived from zirconium propoxide and 3,3′,6,6′-I4BINOL was found to be effective in this reaction, and the desired optically active 2,3-dihydro-4-pyridone derivatives were obtained with high enantioselectivities. Asymmetric formal synthesis of a natural product
Indium(i) iodide-catalyzed regio- and diastereoselective formal α-addition of an α-methylallylboronate to N-acylhydrazones
作者:Shū Kobayashi、Hideyuki Konishi、Uwe Schneider
DOI:10.1039/b802153h
日期:——
Indium(I) iodide was found to catalyze the formal α-addition of an α-methylallylboronate to various N-acylhydrazones, in the presence of an alcohol additive, to afford the corresponding anti-α-adducts with high regio- and diastereoselectivity in high yields.
Zirconium-Catalyzed Enantioselective [3+2] Cycloaddition of Hydrazones to Olefins Leading to Optically Active Pyrazolidine, Pyrazoline, and 1,3-Diamine Derivatives
作者:Yasuhiro Yamashita、Shū Kobayashi
DOI:10.1021/ja049498l
日期:2004.9.1
conducted in high yields with high enantioselectivities using a chiral zirconium catalyst. These reactions open ways to synthetically and biologically important pyrazoline, pyrazolidine, and 1,3-diamine derivatives. Further, several experiments suggested that the reactions proceeded via concerted pathways.
Cyanation of N-acylhydrazones using trimethylsilylcyanide (TMSCN) proceeded well in the presence of an amine to afford the corresponding α-hydrazinonitriles in high yields. For less reactive substrates, the combined use of an amine and a catalytic amount of scandium triflate [Sc(OTf)3] was effective to promote the reactions. The mechanistic study suggested that the amine worked as a Brønstedbase