Ultrasound-promoted access to Baylis–Hillman amines

Abstract

It is surveyed that the amination of the Baylis-Hillman acetates with primary amines can be dramatically promoted in improved yields and shortened reaction time under ultrasound irradiation than those under conventional stirring. The extensive scope of both amines and acetates are screened to investigate the relationship between substituents and their performance in such transformation.

Synthesis of 1,3-Dialkyl-1,2,3-triazolium Ionic Liquids and Their Applications to the Baylis−Hillman Reaction

“…In particular, the reactions with acrylic esters were quite sluggish, and the hydrolysis of acrylic esters in aqueous media could be a potential side reaction . To circumvent these problems, several reaction conditions have been developed using supercritical CO 2 , ultrasound, microwave irradiation, and ionic liquids . Most notably, the use of ionic liquids as an alternate solvent has been extensively studied for the past decade …”

Metal catalyst-free N-allylation/alkylation of imidazole and benzimidazole with Morita–Baylis–Hillman (MBH) alcohols and acetates

“…Moreover, the addition of additives to the previous reaction mixture, such as DMAP [24][25][26]31] or molecular sieves 4 Å, commonly used to mediate nucleophilic allylic substitutions, did not lead to a notable improvement of the reaction outcome (Table 2, entries 2 and 3). However, the use of DABCO, commonly used as a powerful catalyst or a nucleophilic additive in the reaction of acyclic MBH adducts with various nucleophiles [21,[34][35][36][37], did not afford the S N 2/S N 2' products but provided the 1,4-adduct 8a in 84% yield (Table 2, entry 4).…”

An Efficient and Recyclable DMAP-Based Ionic Liquid/Water System for Morita–Baylis–Hillman Reactions

“…To circumvent the sluggish problem of the reaction and to improve the efficiency, numerous physical and chemical methods have been developed to increase the reaction rate. [3][4][5][6][7][8][9][10] Several novel solvent media have been applied to the Morita-Baylis-Hillman reaction. Protic media were used to accelerate the Morita-Baylis-Hillman reaction through stabilisation of the enolate intermediate by hydrogen bonding.…”