Regioselective Alkylation of Anthrone, 5,5-dimethyl-3-isoxazolidinone and 4-methylquinolone by phase transfer catalysis

Divergent Synthesis of Polymethoxylated 4-Aryl-2-quinolones

Polymethoxylated 4-aryl-2-quinolones were synthesized from the corresponding (o-aminophenyl)propiolates via Cu-catalyzed hydroarylation and subsequent deprotection/lactam formation. Selective iodination of the C3 position of the product followed by coupling reactions of the resulting 3-iodinated 4-aryl-2-quinolone afforded 3-substituted-4-aryl-2-quinolones. Moreover, the N-benzyl protecting group was successfully replaced with other polyoxygenated benzyl groups.

Synthesis-guided structure revision of the sarcodonin, sarcoviolin, and hydnellin natural product family

A sweeping structural revision of the sarcodonin natural product family (published structures 1a-13a) is proposed after extensive studies aimed at their chemical synthesis. Key features of revised structure 1b include replacement of the N,N-dioxide moiety with an oxime, ring-opening of the central diketopiperazine, and transposition of the terphenyl wing from the 1β-2β position of 1a to the 2β-3β position of 1b. This structure revision arose from the serendipitous synthesis of a benzodioxane aminal (44) whose structure was unambiguously determined by X-ray crystallography and whose spectral properties bore considerable resemblance to the published data for the sarcodonins. A versatile new method for O-arylation of hydroxamic acids is also reported herein, as well as a manganese(III)-mediated α-oxidation of hydroxamic acids to aminals.