# Photocatalytic remote C(sp3)–H alkylation of long-chain alkenes: A tandem multicomponent approach via radical translocation

## TL;DR

A new metal-free photocatalytic method enables selective alkylation of alkenes, producing complex molecules with high efficiency and versatility.

## Contribution

A redox-neutral, transition-metal-free tandem multicomponent reaction for remote C(sp3)–H alkylation and perfluoroalkylation of alkenes.

## Key findings

- The method achieves diverse 1,n-difunctionalized patterns in unactivated alkenes via radical translocation.
- A tandem sequence involving HAT processes synthesizes trans-1,2-disubstituted cyclopentanes efficiently.
- The reaction is scalable and allows conversion of products into valuable functional groups.

## Abstract

A breakthrough in organic synthesis has been accomplished by developing a redox-neutral, transition-metal-free tandem multicomponent reaction that combines perfluoroalkylation with the remote C(sp3)–H alkylation of terminal alkenes. This method exhibits exceptional chemo- and regioselectivity, leveraging organophotocatalysis under mild conditions. The versatility of this methodology is demonstrated through diverse 1,n-difunctionalized patterns (1, 6, 1, 7, 1, 11, and 1, 14) in unactivated alkenes through controlled radical translocation between secondary C(sp3)–carbon atoms, despite their similar bond dissociation energies (BDEs). Additionally, the study introduces a tandem multicomponent sequence encompassing the trifluoromethylation, 5-exo-trig cyclization, 1,5-radical translocation, and subsequent C(sp3)–H alkylation of 1,6-dialkenes to synthesize trans-1,2-disubstituted cyclopentanes. A key achievement of this work is the development of a multicomponent, transition-metal-free, tandem reaction for synthesizing highly substituted cyclopentane derivatives. This sequence involves two consecutive hydrogen atom transfer (HAT) processes: first, a 1,5-HAT from a secondary C(sp3)–carbon to a tertiary C(sp3)–carbon, followed by a 1,6-HAT from a vinylic carbon to a secondary carbon. This approach demonstrates excellent synthetic utility, as evidenced by its scalability and the facile conversion of the obtained products into diverse valuable functional groups, highlighting the broad applicability and potential of this innovative strategy.

A redox-neutral, metal-free organophotocatalytic tandem reaction enables the selective perfluoroalkylation and remote C(sp3)–H alkylation of alkenes, delivering diverse 1,n-difunctionalization and substituted cyclopentanes via controlled HAT.