Herein, we present a method for the diastereoselective synthesis of N-heterocycle-substituted cyclobutanes from commercially available bromocyclobutanes. This method enables the efficient formation of various heterocyclic aminocyclobutane esters and amides using simple reagents. Notably, N-nucleophiles such as imidazoles, azoles, and nucleobase derivatives were successfully incorporated, enhancing the chemical diversity of small ring building blocks for medicinal chemistry applications.