A relay ring-closing metathesis/Diels-Alder approach to sugar-derived pluramycin-hybrids

Herein, we present a general approach for synthesizing pluramycin hybrids, which are analogous to the pluramycinone carbocyclic skeleton. This method involves a sequence of relay ring-closing enyne metathesis, Diels-Alder and oxidative aromatization reactions to synthesize pluramycinone-sugar hybrids. As part of our ongoing research, we have successfully synthesized two pluramycin hybrid analogues by carefully monitoring the late-stage oxidative aromatization steps, which depend on the stereo-orientation of the Diels-Alder cycloadduct at the C-4 center. The undesired ring-opening product can also serve as a C-glycoside analog, providing a versatile convergent route to access both types of hybrids and highlighting the significance of this strategy.

A new and informative [a,b,c,d] nomenclature for one-pot multistep transformations: a simple tool to measure synthetic efficiency

Domino, cascade and tandem reactions constitute the most efficient and creative chemical transformations with a huge domain of synthetic utility and applications. A number of reactions may be achieved in a single pot, accompanied by the formation of new rings and new bonds, leading towards higher molecular complexity. A lack of one unified, yet informative descriptor often understates the synthetic ingenuity of certain highly creative transformations. In this review, we propose a new tetra-coordinated [a,b,c,d] nomenclature which takes into account and displays the basic parameters which generally indicate the level of efficiency of a chemical transformation. An almost exhaustive set of one-pot multistep reactions may be described by this system and this review is an attempt to display the one-pot multistep transformations reported from our group and to classify them based on our proposed descriptor.

Stereoselective synthesis and antitumoral activity of Z-enyne pseudoglycosides

The stereoselective synthesis and antitumoral activity of Z-enyne pseudoglycosides is described.