2,3-Diphenyl-, 2-methyl-3-phenyl-, and 2-methyl-3-(4-methylphenyl)cyclopropenone oxime hydrochlorides (3) were prepared in good yields from the corresponding cyclopropenones and hydroxylamine hydrochloride in methanol. The salts 3 reacted with alkyl and aryl isocyanates in the presence of triethylamine to afford 1:2 addition products 4,6-diazaspiro[2.3]hexenones in moderate yields. In contrast, acetone
Palladium-Catalyzed Ring-Opening Alkynylation of Cyclopropenones
作者:Takanori Matsuda、Yusuke Sakurai
DOI:10.1002/ejoc.201300220
日期:2013.7
N-Heterocyclic carbene–palladium catalysts are used to promote addition/ring opening of cyclopropenones with terminal alkynes. The ring-opening alkynylation affords alkenyl alkynyl ketones in good yields. For reactions with propargylic esters having an aryl or alkenyl substituent at the propargylic position, [3+2] annulation occurs exclusively to give 4-methylenecyclopentenones.
reported that combines a cycloaddition reaction with a regioselective strain‐release process to afford diverse heterocyclic frameworks through bifunctional catalysis. The cooperation of hydrogen‐bonding network activation and a regiodivergent strain‐assisted effect is the key to promoting this complex chemical transformation, leading to the generation of two different ring systems in high yields with excellent
Fully Substituted Conjugate Benzofuran Core: Multiyne Cascade Coupling and Oxidation of Cyclopropenone
作者:Liangliang Yao、Qiong Hu、Li Bao、Wenjing Zhu、Yimin Hu
DOI:10.1021/acs.orglett.1c01304
日期:2021.7.2
multiyne cascade coupling has been developed. This chemistry provides a novel, simple, and efficient approach to synthesize fullysubstituted conjugate benzofuran derivatives from simple substrates under mild conditions. The density functional theory (DFT) calculations reveal that the unique homolytic cleavages of cyclopropenone and molecular oxygen are crucial to the success of this reaction.
saturated oxygenheterocycles, providing an efficient method for the synthesis of 3-haloacrylates. The ring-opening reaction enables the construction of two C–X (X = Cl, Br, or I) bonds and a C–O bond as well as the cleavage of two C–O bonds and a C–C bond in a single step. This protocol is highly atomeconomical, has an excellent substrate scope, and exhibits the ability for gram-scale reaction.