Facile construction of novel imidazolidine-spirooxindoles via diastereoselective cycloaddition of N-acylhydrazine-derived imines with 3-isothiocyanato oxindoles
presence of 10 mol% of Na2CO3, the desired imidazolidine-spirooxindoles were obtained in 81–99% yield with up to 99 : 1 dr by means of the diastereoselective [3 + 2] cycloaddition of N-acylhydrazine-derived imines with 3-isothiocyanatooxindoles. Single-crystal X-ray structure analysis was conducted to determine the relative stereochemistry of the imidazolidine-spirooxindoles. Diastereoselective access
在存在10 mol%的Na 2 CO 3时,通过衍生自N-酰基肼的非对映选择性[3 + 2]环加成反应,可以81-99%的收率获得所需的咪唑烷-螺氧并吲哚,最高可达99:1 dr。亚胺与3-异硫氰酸根合吲哚。进行了单晶X射线结构分析,以确定咪唑烷-螺氧还吲哚的相对立体化学。拟议的机制假设非对映选择性进入咪唑烷-spirooxindoles。
A simple and efficient method for the synthesis of α-(N′-acylhydrazino)-substituted phosphonates has been developed using the hydrophosphonylation of benzoylhydrazones with triethyl phosphite in the presence of iodine as a catalyst at room temperature. The products are formed in excellent yields (89-95%) within two to three hours.
Allylation of N-Benzoylhydrazones (=N′-Alkylidene-Substituted Benzohydrazides) by Treatment with Allyl Bromide in the Presence of Zinc in Aqueous Ammonium Chloride Solution
N‐Benzoylhydrazones (=N′‐alkylidene‐substituted benzohydrazides) 1 are allylated efficiently by reaction with allyl bromide (2) in the presence of Zn in aqueous NH4Cl solution. The products 3 are formed in excellent yields (85–94%) within 35–50 min (Scheme, Table).
Ñ -Benzoylhydrazones(= N' -亚烷基-取代的benzohydrazides)1是由用烯丙基溴(反应有效地烯丙基化2中的Zn的在含水NH存在下)4 Cl溶液。产品3在35-50分钟内以优异的产率(85-94%)形成(方案,表)。