Jun-Jie Yin

Correction to: Nature Chemistry https://doi.org/10.1038/s41557-026-02156-z, published online 1 June 2026. In the version of the article initially published, the reference “Liang, Y. et al. Nitrene equivalent mediated metal-free ring expansions of alkylidenecyclopropanes and an alkylidenecyclobutane. Org. Lett. 8, 5877–5879 (2006)” was missing and has now been added as ref. 40 to the second paragraph of the “Strategies” section, in the sentence beginning “In contrast to the aryl-substituted ACPs”.

Abstract Cyclobutane amino nitriles (CBANs), as a class of sterically hindered α,α-disubstituted unnatural amino acid derivatives, have garnered notable interest in pharmaceutical research due to their capacity to enhance molecule potency, metabolic stability and selectivity. However, the advancement and exploration of the chemical space of CBANs are impeded by general synthetic strategies, particularly for sterically more hindered vicinal tetrasubstituted derivatives.