Aliphatic Aldehydes: Novel Radical Alkylating Reagents

The emergence of radical chemistry has driven chemists to develop general and efficient radical reactions as well as to discover safe and cost-effective radical sources. Among the various transformations, the radical-involved alkylation reaction continues to blossom since the alkyl unit is ubiquitous in biological and pharmaceutical compounds. The utilization of aliphatic aldehydes as alkyl radical precursors via peroxides or oxygen-initiated decarbonylation reactions has attracted great attention over the past decade due to their ready availability and the simple operation. Although examples of radical acylation reactions starting from aldehydes have been reviewed before, reviews on decarbonylative radical reactions of aliphatic aldehydes are scarce. In this review, we summarize recent significant advances in this rapidly growing area, mainly focusing on reaction design and reaction mechanisms.