Design, Synthesis and Biological Evaluation of Strigolactone and Strigolactam Derivatives for Potential Crop Enhancement Applications in Modern Agriculture.

Strigolactones have been known as signaling molecules in the rhizosphere of plants since more than 50 years. However, their roles as phytohormone have been only recognized since 2008. We describe here a very efficient synthetic access to representative canonical strigolactones displaying the A-B-C-D tetracyclic structure and to non-canonical strigolactones as carlactonoic acid and methyl carlactonoate. In addition, we report the design and the synthesis of strigolactams as promising derivatives of strigolactones for potential use in modern agriculture. Among the synthetic methods developed for this project, the intramolecular [2+2] cycloaddition of keteneiminium salts to C=C bond has been particularly useful to the synthesis of natural strigolactones and their potentially improved analogues.