Synthesis of a 2(1H)-pyridone library via rhodium-catalyzed formation of isomunchones.

Through the use of the dipolar cycloaddition of isomunchones with olefins the 2(1H)-pyridone ring system has been synthesized. (1) The use of different cyclization partners followed by diversification of the initial scaffold has provided libraries of 4-hydroxy-2(1H)-pyridones. There are no examples of this ring system in either PubChem or the MLSMR.

An unusual oligomerization/oxidation reaction of a 3-boron-substituted 1-phenylbuta-1,3-diene produces 6,9,16,19-tetraphenyl-5,15-distyryl-3,13,25,26-tetraoxa-2,12-diborapentacyclo[16.2.2.2(8,11).1(2,5).1(12,15)]hexacosa-1(20),7,10,17-tetraene.

The unusual title macrocyclic structure, C60H54B2O4, has been isolated from exposure of 3-BF(3)-1-phenylbuta-1,3-diene to both air and moisture in an attempt to obtain crystals of the starting butadiene compound. Formation of the macrocycle from six molecules of the starting butadiene material is rationalized and its structural features are compared with those of other B(OR)2-substituted cyclohexane and benzene ring containing structures. Molecules reside on crystallographic centers of inversion and there are no intermolecular interactions of note in the crystal structure.

Preparation of 2-BF3-substituted 1,3-dienes and their Diels-Alder/cross-coupling reactions.

[reaction: see text] 2-BF3-substituted 1,3-butadienes with potassium and tetrabutylammonium counterions have been prepared in gram quantities from chloroprene via a simple synthetic procedure. The potassium salt of this new main group element substituted diene has been characterized by 1H, 13C, 11B, and 19F NMR. Diels-Alder reactions of these dienes with ethyl acrylate and methyl vinyl ketone are reported, as well as subsequent Pd-catalyzed cross-coupling reactions of those Diels-Alder adducts.