Synthesis and reactions of allenes with sulfur ylides

• Grant number: 25/06187-2
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: August 01, 2025
• End date: April 30, 2029
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Organic Chemistry
• Principal Investigator: Antonio Carlos Bender Burtoloso
• Grantee: João Pedro Arantes Campos
• Host Institution: Instituto de Química de São Carlos (IQSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil

Abstract

It is known that sulfur ylides are classes of extremely versatile molecules that can be used to carry out a series of important reactions within organic synthesis. This class of molecules has shown reactive compatibility with various organic functions: olefins, carbonyls, alkyl halides, and alkynes. Among the wide variety of differently substituted alkynes that have been used to react with sulfur ylides, we note that the vast majority of cases require catalysis, often with transition metals.In this research project, one of the ideas is to use sulfoxonium ylides, important synthetic tools, to carry out additions to very specific systems: alkynes linked to cyclopropanes or functionalized epoxides. The main synthetic idea is that, after the attack of the sulfur ylide on one of the carbons of the triple bond, the ¿ system of the triple bond is delocalized to form a double bond and promote the formation of a rather peculiar functionality within organic chemistry: allenes.Allene arrangements contain two ¿ perpendicular systems to each other, and depending on the correspondence of their substituents, there may be an axis of chirality. Therefore, like sulfur ylides, allenes, in addition to acting as excellent building blocks, can control the formation of stereogenic centers. The synthesized products, after the opening of any of the proposed cyclic systems, should contain in their structure allenes and ylides, two extremely versatile functionalities within organic chemistry, which, as far as we know, have not yet been reported.Another possibility proposed in this project is to use cyclic allenes to act as electrophiles towards ylides. This is a reactivity similar to the chemistry of benzynes, already explored by Prof. Burtoloso's group, but with its unique peculiarities. Different systems of strained cyclic allenes can be used: containing heterocycles (oxygen or nitrogen) or only carbon atoms.It is important to emphasize that nitrogen heterocyclic structures can give rise to functionalized alkaloids, if we consider that successive reactions can be carried out with these molecules. The products obtained in these two proposals have great potential to act as building blocks for obtaining structurally more complex and highly functionalized compounds. Furthermore, this is a completely new proposal for obtaining sulfoxonium ylide compounds functionalized at the beta position.