Over the last two decades, transition-metal catalyzed C-H functionalization of indoles has emerged as an area of extensive research and tremendous progress has been made in this regard. Early developments...

Reported herein is an unprecedented reactivity of propargyl alcohols as “Three-Carbon Synthons” in a Rh(III)-catalyzed C-H functionalization of acetanilides, leading to the synthesis of core structures of isocryptolepine, gamma-carbolines, dihydrochromeno[2,3-b]indoles, and diindolylmethanes derivatives. The transformation involves a Rh(III)-catalyzed C-H functionalization and heteroannulation to yield indoles followed by a cascade cyclization with both external and internal nucleophiles to afford diverse products. The role of the hydroxy group, the key function of the silver additive, the origin of the unique reverse regioselectivity and the rate-determining step, are rationalized in conformity with the combination of experimental, noncovalent interaction analysis and DFT studies. This protocol is endowed with several salient features, including one-pot multistep cascade approach, exclusive regioselectivity, high bond-forming efficiency, and synthesis of a variety of molecular frameworks.

Allenes are unique coupling partners in transition-metal-catalyzed C–H functionalization leading to a variety of products via alkenylation, allenylation, allylation, and annulation reactions. The outcome is governed by both the reactivity of the allene and the formation and stability of the organometallic intermediate. An efficient Rh­(III)-catalyzed, weakly coordinating group-directed dienylation of electronically unbiased allenes is developed using an N-acyl amino acid as a ligand. Further elaboration of the dienylated products to construct polycyclic compounds is also described.

No abstract

Reported herein is a reactivity of propargyl alcohols as “Three‐Carbon Synthons” in a Rh(III)‐catalyzed C−H functionalization of acetanilides, leading to the synthesis of core structures of isocryptolepine, γ‐carbolines, dihydrochromeno[2,3‐b]indoles, and diindolylmethanes (DIM) derivatives. The transformation involves a rhodium(III)‐catalyzed C−H functionalization and heteroannulation to yield indoles followed by a cascade cyclization with both external and internal nucleophiles to afford diverse products. The role of the hydroxy group, the key function of the silver additive, the origin of the reverse regioselectivity and the rate‐determining step, are rationalized in conformity with the combination of experimental, noncovalent interaction analysis and DFT studies. This protocol is endowed with several salient features, including one‐pot multistep cascade approach, exclusive regioselectivity, good functional group tolerance and synthesis of variety of molecular frameworks.