The asymmetricring‐opening/cyclization of cyclopropyl ketones with primary amine nucleophiles was catalyzed by a chiral N,N′‐dioxide/scandium(III) complex through a kinetic resolution process. A broad range of cyclopropyl ketones and primary amines are suitable substrates of this reaction. The corresponding products were afforded in excellent enantioselectivities and yields (up to 97 % ee and 98 %
An organocatalytic Cloke–Wilson rearrangement of cyclopropyl ketones to 2,3-dihydrofurans is exploited utilizing the homoconjugate addition process. With 1,4-diazabicyclo[2.2.2]octane as the catalyst, the rearrangement in DMSO at 120 °C proceeded in generally high yields, exclusive regioselectivity, and a broad substrate scope. An examination of the mechanism including stereochemical analysis and intermediate
The asymmetricring‐openingreaction of cyclopropyl ketones with indoles has been realized by using a N,N′‐dioxide/scandium(ΙΙΙ) complex as catalyst. The corresponding 3‐alkylated indole derivatives were obtained in moderate to excellent yields with good ee values. Moreover, a possible transition state was proposed on the basis of experimental studies and X‐ray structure of product.
A sustainable strategy by internally recycling an organocatalyst as a reactant in a downstream reaction to improve the atomefficiency of organocatalytic tandem reactions is described. Specifically, a one-pot tandem Cloke–Wilson/Boulton–Katritzky reaction of cyclopropylketones with a hydroxylamine has been developed for the synthesis of fully substituted isoxazoles, in which the hydroxylamine serves
Visible-light-induced metal-free trifluoromethylation of activated, carbocyclic, and unactivated vinylcyclopropanes via a ring-opening reaction using the Langlois reagent (CF3SO2Na) is reported to synthesize allylic trifluoromethylated derivatives. Allylic trifluoromethylation was achieved by a photo-oxidative single electron transfer (SET) process at an ambient temperature and under metal-free conditions
据报道,使用Langlois试剂(CF 3 SO 2 Na)通过开环反应,可见光诱导的活化,碳环和非活化乙烯基环丙烷的无金属三氟甲基化反应可合成烯丙基三氟甲基化衍生物。烯丙基三氟甲基化是通过在环境温度和无金属条件下通过光氧化单电子转移(SET)工艺以及使用吡喃鎓盐作为光氧化还原催化剂的可见光照射实现的。所报道的方法具有操作简单,基材范围广,官能团耐受性高和可扩展性的特点。