Sequential Metal Catalysis towards 7-Oxostaurosporine and Its Non-Natural Septanose Analogue.

We report sequential metal catalysis towards indolocarbazole glycosides. The signature event is highlighted by i) Pd0 -catalyzed addition of indolocarbazole to alkoxyallene combined with ring-closing-metathesis; ii) Ru-catalyzed chemoselective olefin migration; iii) PdII -catalyzed oxidative cyclization to build the bicyclic core structure of the target compounds. This approach gave access to both natural pyranose- and non-natural septanose glycosides. A short formal synthesis of 7-oxostaurosporine was achieved via this strategy.

Palladium-Catalyzed Asymmetric Nitrogen-Selective Addition Reaction of Indoles to Alkoxyallenes.

A new palladium-catalyzed asymmetric addition reaction of indoles to alkoxyallenes is reported. Remarkably, the reaction showed complete regioselectivity toward the nitrogen. A new mechanism distinct from that of conventional π-allyl chemistry is proposed to explain this unique selectivity. The utility of the reaction is demonstrated by highly efficient and flexible synthesis of N-glycosylindoles.

Pd-Catalyzed Regioselective Asymmetric Addition Reaction of Unprotected Pyrimidines to Alkoxyallene.

Catalytic asymmetric synthesis of N-heterocyclic glycosides free of protecting and directing groups is reported. The key reaction is highlighted by the atom-efficient and regioselective addition of unprotected pyrimidines to highly functionalized alkoxyallene. Numerous acyclic and cyclic N-heterocyclic glycosides are accessed with minimal formation of organic byproducts. The synthetic utility of the reaction is demonstrated by the first catalytic asymmetric synthesis of anticancer pharmaceutical (-)-Tegafur and stereoselective synthesis of an oxepane nucleoside derivative.