Highly Efficient Three-Component Synthesis of β-Lactams fromN-methylhydroxylamine, Aldehydes, and Phenylacetylene

N-Benzylhydroxylamine as a novel synthetic block in "C1N1" embedding reaction via α-C(sp3)-H activation strategy

A novel process using N-benzylhydroxylamine hydrochloride as a "C1N1 synthon" in [2+2+1] cyclization for the construction of 1,2,5-trisubstituted imidazoles has been described for the first time. The key to realizing this process lies in capturing arylamines by in situ generated novel acyl ketonitrone intermediates. Subsequent tautomerization activates the α-C(sp3)-H of N-benzylhydroxylamines, and thus breaks through its inherent reaction mode and achieves N, α-C site-selective cyclization. Furthermore, this method enables scale-up synthesis and late-stage modification of complex molecules.

Direct, catalytic synthesis of carbapenams via cycloaddition/rearrangement cascade reaction: unexpected acetylenes' structure effect

Reactions of acetylenes derived from glyceraldehyde and propargyl aldehyde show remarkable reactivity in Kinugasa cycloaddition/rearrangement cascade process catalyzed by Cu(I) ion. Reactions proceed by formation of a rigid dinuclear copper(I) complex in which each copper ion is coordinated to one or both oxygen atoms in the acetylene molecule and to both triple bonds. It has been demonstrated that one oxygen atom can be replaced by the phenyl ring, which is able to coordinate the copper ion by the aromatic sextet. Kinugasa reactions that proceed in a high yield can also be performed in the presence of a catalytic amount of the copper salt to provide products in an acceptable yield without a decrease of diastereoselectivity.

Copper-catalyzed coupling of tertiary aliphatic amines with terminal alkynes to propargylamines via C-H activation

We have developed a convenient and efficient method for coupling of tertiary aliphatic amines with terminal alkynes to propargylamines via C-H activation. The protocol uses CuBr as the catalyst, NBS as the free radical initiator, CH(3)CN as the solvent, and the alkynylation was selectively performed on the methyl of tertiary aliphatic amines at 80 degrees C. This is an economical and practical method for the synthesis of propargylamines.