TEMPO Mediated Cyclopropanols Ring Opening C−N Cross‐Coupling with Nitrogen Nucleophiles

Abstract

A feasible and umpolung strategy for the synthesis of structurally diverse β-amino ketones has been achieved through TEMPO mediated CÀ N coupling of cyclopropanols with nitrogen nucleophiles. Mechanism studies indicated that in situ generated enones derived from cyclopropanols are the key intermediates and TEMPO play multiple roles, including radical initiator, trapping reagent, a porter of β-hydrogen and an in situ base. This protocol features broad substrate scope, good scalability and good to excellent yields and provides an alternative and complementary approach to the synthesis of structurally important β-amino ketone scaffolds under metal and additive-free conditions.

Copper-catalyzed 4-HO-TEMPOH mediated phosphorylation of alkenes

“…Based on the above experimental results and previous reports, 9,10 we proposed a plausible mechanism for the phosphorylation of alkenes (Fig. 1).…”

Copper(I)‐Catalyzed [4+2] Oxidative Annulation of α,β‐Unsaturated Ketoxime Acetates with Cyclopropanols toward Functional Pyridines

“…A radical clock experiment was also conducted by subjecting vinylcyclopropane 6 into the model reaction, and product 3 aa was obtained in 60% yield while the radical trapping product was not detected. The experiment indicated that β-keto alkyl radical generated from 2 a in the previous work [15] was not involved as reactive intermediate in this transformation (Scheme 5g).…”

Ring‐Opening Functionalization/Cyclization Reactions of Cycloalkanols under Transition‐Metal‐Free Conditions

“…In 2023, Zhan and co-workers reported TEMPO-mediated CÀ N cross-coupling of cyclopropanols with nitrogen nucleophiles under metal-free and additive-free conditions, affording multifarious structurally importan β-amino ketones in good to excellent yields (Scheme 10). [26] A broad range of cyclopropanols together with nitrogen nucleophiles were shown to be viable substrates in this transformation, while phenylcyclobutanol was not compatible with this reaction system. The authors noted that the reaction system were also compatible with the C and O centered nucleophiles.…”