Studies on Knoevenagel condensations between conjugated dienals and 4-hydroxy-2-pyridone/quinolone-type 1,3dicarbonyl equivalents led to the development of a simple one-pot strategy to access citridone A and related synthetic cyclopenta[b]furopyridones/quinolones. The present work highlights the power of domino cascades in the synthesis of natural product frameworks and may help promote future studies on this promising new class of pyridone alkaloids.

The decomposition of diazodicarbonyl compounds in the presence of various metal catalysts has become a reliable method for the functionalization of indoles via carbenoid intermediates. Exploiting the nucleophilic reactivity of the in situ generated malonic ester product formed, we herein report a tandem C-H functionalization/Conia-ene cyclization of N-alkyne tethered indoles. This double functionalization of diazodicarbonyls generates a range of pyrrolo[1,2-a]-, pyrido[1,2-a]-, and azepino[1,2-a]indole products with good synthetic efficiency.

Reaction of peroxides with glycals, when carried in the presence of NIS affords2-deoxy-2-iodo-a-glycosides in good yields with predominant trans-diaxial selectivity at rt. Under photolytic conditions in the presence of catalytic eosin Y, the reaction leads to 2-deoxyglycosides or 2,3-unsaturated-a-glycosides.NIS plays two roles firstly, to form an iodonium ion with the glycal and secondly to bring about the decomposition of the organic peroxide into an alcohol that reacts with the activated sugar whereas blue LED light and Eosin Y bring about a radical-mediated glycosylation to give the a-2-deoxy glycoside or 2,3-unsaturated glycosides based on the protecting group at C-3 position of glycals.