Structure–Activity Relationship of Formamides as Organocatalysts: The Significance of Formamide Structure and Conformation

The impact of the structure and conformation of formamides as organocatalysts was investigated and reported herein as a structure–activity relationship. Selected formamides and some amides were evaluated for their ability to activate allyltrichlorosilane in the allylation of benzaldehyde. The results suggest that the reactive conformation of secondary formamides is the less‐favorable cis conformation, whereas tertiary formamides and most amides are less reactive or unreactive in the reaction. A trend is observed between the Charton value for the N ‐substituent on the secondary formamides and the amount of product formed, with an increase in yield as the substituent becomes larger. This work highlights the effects of sterics and solvent polarity on the reactivity of formamides.