N-Alkylsulfonamides as Useful Carbon Electrophiles

Abstract

The cleavage of the sp³ carbon–nitrogen bonds in <i>N</i>-alkylsulfonamides has been utilized for the selective formation of various carbon–carbon and carbon–heteroatom bonds. When <i>N</i>-alkylsulfonamides undergo sp³ carbon–nitrogen bond cleavage in the presence of acid catalysts, the resulting carbocations can react with a broad range of carbon, sulfur, nitrogen, oxygen, or hydride nucleophiles. On the other hand, basic conditions allow<i> N</i>-alkylsulfonamides to act as sp³ carbon electrophiles in reactions with strong nucleophiles. In general, <i>N</i>-benzylic, <i>N</i>-allylic, and <i>N</i>-propargylic sulfonamides serve as suitable substrates, and their reactions with nucleophiles provide ready access to a wide range of functionalized molecules. 1 Introduction 2 Mechanism 3 Reactions with Carbon Nucleophiles 3.1 Active Methylene Compounds 3.2 Ketones and Aldehydes 3.3 Aromatic Compounds 3.4 Alkynes, Alkenes, and Arylallenes 3.5 Silylated Carbon Nucleophiles 3.6 Grignard Reagents 4 Reactions with Sulfur Nucleophiles 4.1 Thiols and Thiophenols 4.2 Thioacetic acid 4.3 Sulfinic Acids 5 Reactions with Nitrogen Nucleophiles 6 Reactions with Oxygen Nucleophiles 7 Reduction 8 Conclusion