Silver-Catalyzed Cross-Dehydrogenative Coupling (CDC) Strategy for the Construction of Dialkyl/Dibenzyl Dibenzo[b,f][1,4]thia-/oxazepin-11-yl Phosphonates

Copper-Catalyzed Phosphorylation of 2,3-Allenoic Acids and Phosphine Oxide: Access to Phosphorylated Butenolides

We investigated a novel Cu-catalyzed annulation of 2,3-allenoic acids with diphenylphosphine oxide, leading to the formation of 4-phosphate butenolides in up to 88% yield. The formation of the C-P bond provides new avenues for the functionalization of different furan-2(5H)-ones, with favorable features such as suitable functional group tolerance and mild synthesis conditions.

Direct Amine-Catalyzed Enantioselective Synthesis of Pentacyclic Dibenzo[b,f][1,4]oxazepine/Thiazepine-Fused Isoquinuclidines along with DFT Calculations

A direct protocol for the asymmetric synthesis of dibenzoxazepine/thiazepine-fused [2.2.2] isoquinuclidines is developed. The reaction proceeds through a proline-catalyzed direct Mannich reaction followed by an intramolecular aza-Michael cascade sequence between 2-cyclohexene-1-one and various tricyclic imines, like dibenzoxazepines/thiazepines, as an overall [4 + 2] aza-Diels-Alder reaction. A series of pentacyclic isoquinuclidines have been prepared, with complete endo-selectivity, in good to high yields and excellent enantioselectivity (>99:1). Density functional theory (DFT) calculations further support the observed high stereochemical outcome of the reaction.

Intramolecular cyclization of imidazo[1,2-a]pyridines via a silver mediated/palladium catalyzed C–H activation strategy

Intramolecular cyclization of imidazo[1,2-a]pyridines has been developed via a C–H activation strategy to reach new chemical-space for drug discovery.

Synthesis of 3-Phenylsulfonylcoumarins by Cyclisation of Phenyl Propiolates with Sulfinic Acids or Sodium Sulfinates

Methods for the synthesis of 3-phenylsulfonylcoumarins by radical sulfonylation cyclisation of phenyl propiolates with sulfinic acids or sodium sulfinates as sulfonyl sources have been developed. A combination of potassium persulfate as oxidant and silver nitrate as catalyst, or tert-butyl hydroperoxide as oxidant and potassium iodide as catalyst were used. The products were formed by an ipso-cyclisation/1,2-ester migration mechanism. The toleration of functional groups is broad and the yield is up to 96%.