Synthesis-Guided Structure Revision of the Sarcodonin Sarcoviolin and Hydnellin Natural Product Family

摘要

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.