A Dual Gold‐Iron Catalysis for a One‐Pot Synthesis of 2,3‐Dihydroisoxazoles from Propargylic Alcohols and N‐Protected Hydroxylamines

Abstract

A concise one-pot route for the synthesis of 2,3-dihydroisoxazoles via a dual gold-iron catalysis has been devised. The method, based on the addition of binucleophilic protected hydroxylamine to propargylic alcohols, enables a one-pot, highly selective synthesis of these heterocycles (10 examples, up to 86% yield).

Gold‐Catalyzed Transformations of Propargyl Alcohols and Propargyl Amines

“…In 2009, Campagne and co‐workers reported a cascade reaction of propargylic alcohols and N ‐protected hydroxylamines (Scheme ) . A propargylic substitution was occurring first, forming hydroxylamine 51 in situ .…”

Direct Nucleophilic SN1‐Type Reactions of Alcohols

“…The activation of the triple bond by using a Au catalyst allowed the intramolecular attack of the hydroxylamine to form the 2,3-dihydrooxazoles. [82] A similar tandem reaction catalyzed by FeCl 3 was applied to the synthesis of furans. [83] Jana, pursuing the methodology of FeCl 3 in the S N 1-type reaction further, presented a novel, www.eurjoc.orgsimple, and straightforward one-pot reaction of alkynes with various alcohols in the presence of iron salts (FeCl 3 and FeBr 3 ) to yield the corresponding alkenyl halides with complete regioselectivity in favor of the E isomer.…”

Supramolecular Alternating Block Copolymers via Metal Coordination

“…Campagne et al10 recently reported cascade reaction sequences initiated by Au‐catalyzed additions of N ‐protected hydroxyamines to propargylic alcohols (Scheme ). The 2,3‐dihydroisoxazoles 30 are obtained by nucleophilic substitution of the hydroxylamines on the propargylic alcohols 28 , followed by 5‐ endo cyclizations of the hydroxy groups onto the alkyne moieties in 29 .…”