A copper(ii) perchlorate-promoted tandem reaction of internal alkynol and salicyl N-tosylhydrazone: direct access to isochromeno[3,4-b]chromene

A copper(ii) perchlorate-promoted tandem reaction of internal alkynol and salicyl N-tosylhydrazone provides a novel, concise method for constructing isochromeno[3,4-b]chromene in 35–94% yields.

Efficient Synthesis of Fused Perhydrofuro[2,3-b]pyrans (and Furans) by Ring Opening of 1,2-Cyclopropanated Sugar Derivatives

[structure: see text]. An efficient method has been developed for the construction of fused perhydrofuro[2,3-b]pyrans by diastereoselective ring opening of 1,2-cyclopropanated sugar derivatives. The methodology has been successfully applied to the synthesis of fused perhydrofuro[2,3-b]pyrano-gamma-butyrolactone derivatives.

'Upenamide: An unprecedented macrocyclic alkaloid from the Indonesian sponge Echinochalina sp

'Upenamide (1) represents a new class of macrocyclic marine alkaloid possessing both spirooxaquinolizidinone and hemiaminal ring systems. It was isolated from the Indonesian sponge Echinochalina sp. The gross structure of 1 was elucidated by spectroscopic methods and accurate mass measurements. A suggestion is made as to its biogenetic origin.