Related Experiment Video
Updated: Aug 14, 2025
![Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F60786.jpg&w=3840&q=50)
Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions
Published on: July 17, 2020
Triazole-enabled, iron-catalysed linear/branched selective C-H alkylations with alkenes
Silvia Cattani1, Andrea Secchi1, Lutz Ackermann2
1Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma, Parco Area delle Scienze 17/A, 43124 Parma, Italy. gianpiero.cera@unipr.it.
Iron-catalysed C-H alkylations of benzamides using alkenes were achieved with N-triazole assistance. This method enables selective synthesis of decorated benzamides, with regioselectivity controlled by olefin choice.
Area of Science:
- Organic Chemistry
- Catalysis
Background:
- C-H functionalization is a key strategy in organic synthesis.
- Developing selective and efficient methods for C-H alkylation remains a challenge.
Purpose of the Study:
- To develop an iron-catalyzed C-H alkylation method for benzamides.
- To investigate the role of N-triazole assistance in directing the reaction.
- To control regioselectivity in the alkylation process.
Main Methods:
- Iron-catalyzed reaction of benzamides with alkenes.
- Utilizing N-triazole as a directing group.
- Varying alkene substrates to study regioselectivity.
Main Results:
- Successful C-H alkylation of benzamides was achieved.
- N-triazole assistance enabled efficient iron catalysis.
- A switch in regioselectivity from linear to branched products was observed based on the alkene used.
- High chemo-, regio-, and site-selectivity were obtained.
Conclusions:
- N-triazole-assisted iron-catalyzed C-H alkylation is a versatile method for synthesizing decorated benzamides.
- The reaction offers tunable regioselectivity, controlled by the choice of olefin.
- This approach provides a valuable tool for constructing complex organic molecules.
Related Concept Videos
02:46Halogenation of Alkenes
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
02:35Electrophilic Addition to Alkynes: Hydrohalogenation
03:08Hydroboration-Oxidation of Alkenes
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
02:38Electrophilic Addition to Alkynes: Halogenation
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.