Studies on the formation of C-C and C-N bonds using late transition metal catalysts

Abstract

Part 1. Copper-Catalyzed Three-Component Reactions

1.Non-Conventional Hydrative Amide Synthesis

It is shown for the first time that N-sulfonyl amides can be efficiently prepared by an unconventional approach of the hydrative reaction between terminal alkynes, sulfonyl azides, and water in the presence of copper catalyst and amine base under very mild conditions. The present route is quite general, and a wide range of alkynes and sulfonyl azides are readily coupled catalytically with water to furnish amides in high yields. A variety of labile functional groups are tolerated under the conditions, and the reaction is regioselective in that only terminal alkynes react while double or internal triple bonds are intact. The reaction can be readily scaled up and is also adaptable to a solid-phase procedure with high efficiency. Furthermore, a wide range of propargyl alcohols and sulfonyl azides react to provide β-hydroxy N-sulfonamides in good to excellent yields. Polyhydroxy amides could be synthesized stereoselectively, proving this as a new practical aldol-surrogate strategy.

2.Preparation of 2-Imino Pyrroles

A new Cu-catalyzed three-component coupling reaction between 1-alkynes, sulfonyl azides, and pyrrole derivatives has been developed for making 2-functionalized pyrrole rings. This C-C bond formation offers high efficiency and selectivity, mild reaction conditions, and a wide substrate scope.

Part 2. Transition-Metal Catalyzed C-H Bond Functionalization: Facile Construction of C-C and C-N Bond

1.Pd-Catalyzed C-H Bond Functionalization of Pyridine N-Oxides

Two catalytic protocols of the oxidative C??C bond formation have been developed on the basis of the C-H bond activation of pyridine N-oxides. Pd-catalyzed alkenylation of the N-oxides proceeds with excellent regio-, stereo-, and chemoselectivity, and the corresponding ortho-alkenylated N-oxide derivatives are obtained in good to excellent yields. Direct cross-coupling reaction of pyridine N-oxides w...