[3+2] Cascade Ring-Closing/Ring-Opening Strategy: Access to N-Indene-Tethered Amino Alcohols

Area of Science:

• Organic Chemistry
• Catalysis
• Synthetic Methodology

Background:

• Developing efficient synthetic routes for complex organic molecules is crucial.
• Rhodium(III)-catalyzed reactions offer powerful tools for C-C bond formation.
• Cascade reactions provide atom-economic pathways to intricate structures.

Purpose of the Study:

• To achieve an unprecedented Rh(III)-catalyzed cascade [3+2] annulation.
• To synthesize novel nitro-functionalized indene-tethered amino alcohols.
• To establish a regioselective and atom-economic synthetic strategy.

Main Methods:

• Utilized a Rh(III)-catalyzed cascade [3+2] annulation reaction.
• Employed 2-aryl oxazoline and α,β-unsaturated nitro olefins as substrates.
• Implemented a synergistic ring-closing/ring-opening strategy.
• Conducted the reaction under mild, silver-free conditions.

Main Results:

• Successfully synthesized a novel series of nitro-functionalized indene-tethered amino alcohols.
• Achieved atom-economic and redox-neutral reaction conditions.
• Demonstrated regioselective cleavage of the C2-O bond of oxazoline.
• Showcased a broad substrate scope for the developed methodology.

Conclusions:

• The developed Rh(III)-catalyzed annulation is an unprecedented and efficient method.
• This strategy offers a novel route to valuable nitro-functionalized indene derivatives.
• The reaction proceeds via a unique synergistic ring-closing/ring-opening pathway.