Pd-Catalyzed C-S Activation/Isocyanide Insertion/Hydrogenation Enables a Selective Aerobic Oxidation/Cyclization
Jian Chang1, Bangyu Liu1, Yang Yang1
1Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis, Faculty of Chemistry, Northeast Normal University , Changchun 130024, China.
Organic Letters
|August 9, 2016
Summary
This study introduces a novel aerobic oxidation method for thioorganics using isocyanides. This process efficiently synthesizes valuable 5-hydroxy-α,β-unsaturated γ-lactams from α-acyl ketene dithioacetals.
Area of Science:
- Organic Chemistry
- Catalysis
- Oxidation Reactions
Background:
- Thioorganic compounds and isocyanides are versatile building blocks in organic synthesis.
- Developing efficient and selective oxidation methods is crucial for synthesizing complex molecules.
- Aerobic oxidation offers an environmentally friendly approach using molecular oxygen.
Purpose of the Study:
- To develop a novel imidoylation reaction of thioorganics with isocyanides.
- To establish an unprecedented aerobic oxidation process for synthesizing γ-lactams.
- To explore the scope and mechanism of this new synthetic route.
Main Methods:
- The reaction was catalyzed by Palladium(II) bis(triphenylphosphine) dichloride (Pd(Ph3P)2Cl2).
- Reactions involved α-acyl ketene dithioacetals and isocyanides in the presence of phenylsilane (PhSiH3).
- The process included C-S bond activation, migratory insertion, hydrogenation, aerobic oxidation, and cyclization steps.
Main Results:
- A wide range of 5-hydroxy-α,β-unsaturated γ-lactams were synthesized.
- The reaction proceeds efficiently under mild conditions, starting under nitrogen and finishing with air exposure.
- The mechanism involves a sequence of key bond formations and transformations.
Conclusions:
- This work presents a unique and efficient method for constructing γ-lactam scaffolds.
- The developed aerobic oxidation process offers a sustainable alternative for synthesizing valuable organic compounds.
- The findings expand the synthetic utility of thioorganics and isocyanides in catalysis.
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