Dearomative Synthetic Entry into the Altemicidin Alkaloids

Area of Science:

• Organic Chemistry
• Natural Product Synthesis
• Medicinal Chemistry

Background:

• Altemicidin and related monoterpene alkaloids from *Streptomyces* exhibit significant cytotoxic and tRNA synthetase inhibitory activities.
• These compounds feature dense, polar azaindane cores and a challenging α-amino acid motif.
• The synthesis and biosynthesis of these alkaloids remain complex challenges in chemical research.

Purpose of the Study:

• To develop a novel, abiotic synthetic strategy for altemicidin.
• To achieve a concise synthesis of altemicidin from readily available chemical feedstocks.
• To address the synthetic challenges associated with the azaindane core and α-amino acid moiety.

Main Methods:

• Exploitation of a dearomative pyridinium addition and dipolar cycloaddition sequence.
• Stereospecific installation of the quaternary amine moiety.
• Chemoselective molybdenum-mediated double reduction for azaindane nucleus formation.

Main Results:

• A concise and distinct abiotic synthesis of altemicidin was achieved.
• The strategy successfully installed the quaternary amine stereospecifically.
• The azaindane core was constructed with minimal redox manipulations using molybdenum catalysis.

Conclusions:

• The developed abiotic strategy offers an efficient route to altemicidin and related alkaloids.
• This synthesis provides a valuable tool for further investigation of their biological properties.
• The methodology simplifies the construction of complex azaindane structures.