Tunable Synthesis of Polysubstituted Pyrroles via Silver-Catalyzed (3 + 2) Cycloaddition of α,β-Unsaturated Nitroketones with Isocyanides

A controlled silver-catalyzed cycloaddition
reaction of α,β-unsaturated
nitroketones with isocyanides has been developed, facilitating the
construction of polysubstituted pyrroles. This protocol addresses
the issue of side reactions associated with the high reactivity of
the aldehyde group in conventional reactions by employing a synergistic
strategy for the protection and deprotection of the aldehyde group.
Additionally, the nitrone moiety stabilizes the cycloaddition transition
state through spatial electronic effects and is spontaneously deprotected
to yield aromatization products.