Cationic dirhodium carboxylate-catalyzed synthesis of dihydropyrimidones from propargyl ureas

Gold Catalyzed 7-endo-dig Hydroaminations Yielding 1,4-Diazepineones

Strategies to access the 1,4-diazepindiones heterocyclic core of the TAN-1057 family of natural products revealed a successful gold-catalyzed hydroamination of yneamide tethered amines. The precursor amino-yneamides are derived from easily accessible 1,2-diamines and alkynoic acids and are efficiently cyclized to the corresponding diazepineones.

Site-selective nitrenoid insertions utilizing postfunctionalized bifunctional rhodium(ii) catalysts

We report a new strategy for the preparation of dirhodium(ii) complexes with the general formula Rh₂(A)₄ that allows the isolation of a dirhodium tetracarboxylate complex with a free amino group available for postfunctionalization. The postfunctionalization of this complex enables the incorporation of a variety of functional groups, including double and triple bonds as well as nucleophilic moieties, thus paving the way to new classes of polymeric as well as bifunctional catalysts, and polymetallic complexes. Furthermore, we demonstrate that a urea containing dirhodium(ii) complex enables site-selective nitrenoid insertions by remote hydrogen bonding control.

(CH3)2CuLi/Cu(OTf)2 Mediated N- or O-Cyclization of Urea-Tethered Cyclobuta[ b]indolines

A (CH₃)₂CuLi/Cu(OTf)₂ mediated N- or O-cyclization of urea-tethered cyclobuta[ b]indolines has been reported in this paper, giving a new synthetic protocol for the construction of pyrimido[1,6- a]indolone and cyclic imidate derivatives in moderate to good yields with a broad substrate scope under mild conditions. A plausible reaction mechanism has been also proposed on the basis of previous reports and the control experiments.

Reactions of secondary propargylamines with heteroallenes for the synthesis of diverse heterocycles

This focused review aims to summarize recent developments in the processes involving additions of secondary propargylamines to various heteroallenes and subsequent transition metal-catalyzed or electrophile-mediated cyclizations.

Syntheses of Cyclic Guanidine-Containing Natural Products

Naturally occurring guanidine derivatives frequently display medicinally useful properties. Among them, the higher order pyrrole-imidazole alkaloids, the dragmacidins, the crambescidins/batzelladines, and the saxitoxins/tetradotoxins have stimulated the development of many new synthetic methods over the past decades. We provide here an overview of the syntheses of these cyclic guanidine-containing natural products.

Crystal structure of 1-(2,4-di-methyl-phen-yl)urea

In the title urea derivative, C₉H₁₂N₂O, the dihedral angle between the benzene ring and the mean plane of the urea group, N—C(=O)—N, is 86.6 (1)°. In the crystal, the urea O atom is involved in three N—H⋯O hydrogen bonds. Mol­ecules are linked via pairs of N—H⋯O hydrogen bonds, forming inversion dimers with an R²₂(8) ring motif. The dimers are linked by further N—H⋯O hydrogen bonds, forming two-dimensional networks lying parallel to (100).

Synthesis of tetrahydropyrimidin-2-ones via FeCl3 catalyzed one-pot domino reaction of amines, methyl propiolate, aromatic aldehydes, and urea

Polysubstituted 3-arylaminoacrylate and tetrahydropyrimidin-2-one derivatives could be selectively produced from the one-pot domino reaction of arylamines, methyl propiolate, aromatic aldehydes, and urea in ethanol in the presence of FeCl3 as catalyst. Under similar reactions secondary amines such as morpholine and piperidine predominately afford tetrahydropyrimidin-2-one derivatives in good yields.