Hyperbaric reactions in organic synthesis. Progress from 2006 to 2021

Abstract

This comprehensive review summarizes the published literature data concerning above 1 kbar reactions for the purposes of preparative organic synthesis (more then 50 mg of the initial substance) from 2006...

High pressure promoted dearomatization of nitroarenes by [4+2] cycloadditions with silyloxydienes

“…Such [4+2] cycloadditions have very negative activation volumes, Δ V ‡ ∼ −25 to −40 mol L −1 , such that their kinetics are almost always accelerated under HP. 13 One of the first examples, and arguably the most emblematic, was by Dauben et al who used furan as a diene in their synthesis of cantharidine. 14 Since then, HP activation has proven useful when performing [4+2] cycloadditions with sterically hindered and electronically deactivated substrates, and in circumstances where the adducts are prone to elimination reactions (as these generally have a positive Δ V ‡ ).…”

Crystal structure and Hirshfeld surface analysis of diethyl (3aS,3a1R,4S,5S,6R,6aS,7R,9aS)-3a1,5,6,6a-tetrahydro-1H,3H,4H,7H-3a,6:7,9a-diepoxybenzo[de]isochromene-4,5-dicarboxylate

“…The DA reaction of furans is typically carried out under thermal conditions, but the use of high pressure has emerged as a powerful tool for enhancing the reactivity and selectivity of this reaction. High pressure can significantly lower the activation energy of the DA reaction, leading to faster reaction rates and improved yields (see reviews by Rulev & Zubkov, 2022;Schettino & Bini, 2007). On the other hand, by the attachment of functional groups, the DA reaction products can participate in various sorts of intermolecular interactions with interesting coordination, supramolecular, catalytic and solvatochromic properties (Gurbanov et al, 2020a,b;Khalilov et al, 2021;Mahmoudi et al, 2017a,b;Mahmudov et al, 2015).…”

Aza‐Michael Reaction: A Decade Later – Is the Research Over?

“…[32] The achievements in hyperbaric realization of aza-Michael reaction have been recently reviewed. [181] The following two examples can be served as an excellent illustration of advantage of the high pressure use. Thus, when the ethyl 2-bromo-4,4,4-trifluorobut-2-enoate 76 is treated with morpholine in ethanol under reflux, the corresponding β-aminoester 77 is isolated as a sole reaction product (Scheme 49).…”

“…Later, the hyperbaric method has been successfully applied for the various Michael acceptors including β,β‐disubstituted ones [32] . The achievements in hyperbaric realization of aza‐Michael reaction have been recently reviewed [181] . The following two examples can be served as an excellent illustration of advantage of the high pressure use.…”