Insights on the Petasis Borono–Mannich multicomponent reaction mechanism

Abstract

The Petasis Borono–Mannich reaction: a joint theoretical and experimental.

Unusual mechanisms in Claisen rearrangements: an ionic fragmentation leading to a meta-selective rearrangement

“…Intrigued by this great difference in reactivity and in order to gather more information concerning the mechanism of this formal α-arylation reaction, we became interested in monitoring this transformation online. Given the abundance of (postulated) positively charged reaction intermediates along the reaction pathway, ESI-MS 11 emerged as a promising tool to observe and intercept those species directly. Additionally, we aimed to complement those studies with quantum chemical calculations and additional experiments.…”

Tuning the Biginelli reaction mechanism by the ionic liquid effect: the combined role of supported heteropolyacid derivatives and acidic strength

“…Therefore, this intermediate shows the behavior of a so-called dead-end intermediate. 57,92 (ii) The results point once more to the Knoevenagel pathway Based on all the obtained results, a catalytic cycle can be proposed (Scheme 4) in the presence and in the absence of the imidazolium-based IL BMI$PF 6 . In the presence of BMI$PF 6 , the Knoevenagel pathway seems to be highly favored.…”

“…46 The need for excess reagents and other drawbacks, such as organic solvent contamination, low yields, long reaction times and no mechanistic evaluation, were also noted. [46][47][48][49] Some of the authors have investigated different features of the multicomponent Biginelli reaction mechanism [50][51][52][53][54] and other MCRs [55][56][57][58] as well as heteropolyacid-catalyzed reactions. [59][60][61][62] In the current work, we disclose the benecial effect of ILs using HPA derivatives on the Biginelli reaction and the mechanistic implications for this MCR.…”

Multicomponent Mannich‐Like Reactions of Organometallic Species

“…This classical version of the Petasis reaction (one substrate bearing a group to coordinate to the boron atom) has continued to spark great interest in the organic chemistry community. In the past few years, further insights into the reaction mechanism have been disclosed, as well as the implementation of alternative conditions such as reactions in water or under solvent‐free conditions in thermal or microwave‐assisted procedures . Several catalysts such as molecular sieves, chitosan, cobalt ferrite nanoparticles, and H 2 Ti 3 O 7 nanotubes have also been assessed in the process.…”