We describe the palladium-catalyzed direct C−H glycosylation of free N-H indole or tryptophan for the stereoselective synthesis of 2-glycosylindoles and tryptophan-C-glycosides. This reaction relies on the ortho-directing transient mediator norbornene, which underwent regioselective C−H functionalization at the indole or tryptophan ring, providing high chemoselectivity. This method offers a more straightforward, stepeconomical, and cost-effective route to construct C-glycosides. The gram-scale amenable building blocks can be further functionalized at C3 and N-H, displaying the robustness of present method.
Pd(II)-Catalyzed, bidentate directing group (BDG)-assisted C(sp 2 )À H functionalization of C2-amido glycals onto the anomeric position is described as a contemporary method for the construction of various unsymmetrical gem-diarylmethyl C-glycosides. Thanks to a bidentate amidoquinoline-type directing group, the insertion of diverse para-quinone methides (p-QMs) onto the pseudoanomeric position of glycal substrates were executed in moderate to good yields. Further functionalization of the final product can be successfully demonstrated by known palladium-catalyzed crosscoupling reactions.
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