Total syntheses of leuconodine B, melodinine E, and leuconoxine were accomplished via a divergent route. The [5.5.6.6]diazafenestrane skeleton was constructed from an indole-3-acetamide derivative via DMDO oxidation to hydroxylindolenine, TMSOTf/2,6-lutidine mediated cyclic aminal formation, and diastereoseletive ring-closing metathesis of a triene derivative.

A novel condensation reaction of carboxylic acids with various non-nucleophilic N-heterocycles and anilides was developed. The reaction proceeds in the presence of di-tert-butyl dicarbonate (BocO), catalytic 4-(dimethylamino)pyridine (DMAP), and 2,6-lutidine and is applicable to the acylation of a wide range of non-nucleophilic nitrogen compounds, including indoles, pyrroles, pyrazole, carbazole, lactams, oxazolidinones, and anilides with high functional group compatibility. The scope of indoles, carboxylic acids, and anilides was also studied.

No abstract

A new Ni/Zr-mediated one-pot ketone synthesis is developed, with use of a mixture of (Me)3tpy·NiII- and py-(Me)imid·NiIICl2-catalysts. The NiI-catalyst selectively activates iodides, whereas the NiII-catalyst activates thio-pyridine esters. An adjustment of a relative loading of the two catalysts allows to tune the relative rate of the two activations and trap a short-lived radical intermediate(s) efficiently. Thus, the new method makes one-pot ketone synthesis highly effective even with a 1:1 mixture of the coupling partners. The synthetic value of the new method is demonstrated with the C-C bond formation at the final stage of a convergent halichondrin-synthesis.

No abstract