Divergent synthesis of pyrrolidine and glutamic acid derivatives using a macrocyclic phase-transfer catalyst under high-pressure conditions

Abstract

The reactivity of the glycine ketimine ester with α,β-unsaturated ketones in the presence of macrocyclic hybrid phase-transfer catalysts under high pressure conditions has been investigated. Control during reactions, obtained through...

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

“…[182] Moreover, it has been recently argued that catalysis has a profound effect on improving selectivity. [183] Therefore, the reactions catalyzed by chiral catalysts could be realized under hyperbaric conditions without loss of selectivity.…”

“…It is very important to note that only little changes in stereoselectivity are observed when moving from atmospheric to high pressure conditions [182] . Moreover, it has been recently argued that catalysis has a profound effect on improving selectivity [183] . Therefore, the reactions catalyzed by chiral catalysts could be realized under hyperbaric conditions without loss of selectivity.…”

Hyperbaric reactions in organic synthesis. Progress from 2006 to 2021

“…Very recently, a convenient high-pressure protocol for the phase-transfer catalyzed reaction between glycine ketamine ester 161 end enones 159 has been developed. 101 The reactivity of substrates could be altered by using an appropriate catalyst and reaction conditions. In the presence of the PTC catalyst ( 164 ), Michael adducts 162 were obtained in high yields and with excellent diastereoselectivity at 10 kbar and r.t. At the same pressure, 1,3-dipolar cycloaddition products 163 were formed in high yields if the reactions were carried out at 50 °C and using catalytic system 165 (Scheme 49).…”

Phosphine Catalyzed Michael-Type Additions: The Synthesis of Glutamic Acid Derivatives from Arylidene-α-amino Esters

“…Considering this last approach, α-substituted glutamates have been mainly obtained via the Michael-type additions of glycine derivatives (glycine templates) onto the corresponding α,β-unsaturated reagents. This reliable strategy employs N -arylidene-α-amino acid esters [ 14 , 15 , 16 ] or tert -butyl N -benzylidieneamino glycinate [ 17 , 18 , 19 , 20 , 21 , 22 ] ( Scheme 1 a) and even activated N -arylideneaminomalonates [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ] ( Scheme 1 b) as starting materials. In all cases, phase transfer catalysis (PTC) conditions or the employment of organic superbases are the most common trends to complete the reaction.…”