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

27 May 2025, Version 1
This content is a preprint and has not undergone peer review at the time of posting.

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.

Keywords

amino alcohols
Mannich reaction
cyclopropanes
homoenolate
stereoselective synthesis

Supplementary materials

Title
Description
Actions
Title
Supporting Information
Description
Experimental procedures and characterization data for new compounds.
Actions

Comments

Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.