Formal Cyclopropylation of Imines with Cyclopropanols: Stereocontrolled Access to Conformationally Constrained γ‐Amino Alcohols

Abstract

Abstract γ‐Amino alcohols are essential motifs in bioactive compounds and chiral catalysts, yet the synthesis of their conformationally constrained variants remains challenging due to the lack of suitable methodologies. Here, we report a formal cyclopropylation of imines with cyclopropanols, enabling the construction of previously inaccessible cyclopropane‐embedded γ‐amino alcohols. This transformation leverages the unique reactivity of enolized zinc homoenolates, which effectively act as a β‐hydroxycyclopropyl anions and engage imines through a sequence of Mannich addition and ring closure. The key to this reactivity lies in the use of bulky N ‐heterocyclic carbene (NHC) ligands, which promote efficient coupling with N ‐sulfonyl aldimines as well as chiral N ‐sulfinyl trifluoromethyl‐ketimines while ensuring excellent diastereocontrol over three contiguous stereocenters. Furthermore, the resulting γ‐amino alcohols can be transformed into β‐ or γ‐aminofunctionalized ketones via homoenolate or β‐keto radical intermediates, offering versatile platforms for downstream derivatization.