Enantioselective Michael addition of α,α-disubstituted aldehydes to maleimides organocatalyzed by chiral primary amine-guanidines

Enantioselective Synthesis of Succinimides by Michael Addition of Aldehydes to Maleimides Organocatalyzed by Chiral Primary Amine‐Guanidines

“…Under these last conditions, the reaction temperature was then decreased to 0 °C to allow the isolation of succinimide ( R )‐ 8aa in quantitative yield with 91 % ee (see Table 1, Entry 19). Thus, the addition of imidazole as an additive allowed for a decrease in the reaction temperature and an increase in the enantioselectivity compared to when no additive was provided 11…”

“…Recently, we reported the use of new chiral primary amine‐guanidines as organocatalysts in the enantioselective addition of α,α‐disubstituted aldehydes to maleimides to give the opposite enantioselectivity to that obtained when related thioureas were used 11. Herein, we present a full account of the use of these new amine‐guanidines as chiral organocatalysts in the asymmetric Michael addition of aldehydes to maleimides to give enantioenriched succinimides, the improvement of the enantioselectivity, and the investigation of the origin of the enantioinduction by employing theoretical calculations.…”

Asymmetric Michael Addition Organocatalyzed by α,β-Dipeptides under Solvent-Free Reaction Conditions

“…The product was purified by flash column chromatography with a mixture of hexanes/EtOAc (7:3) as eluent. The absolute configuration of the products was assigned by comparison with the available literature [ 45 , 55 , 56 , 57 , 76 , 77 ]. The enantiomeric ratio was determined by chiral HPLC.…”

“…In 2007, Cordova’s research group [ 54 ] was the first to study the addition reaction of isobutyraldehyde to maleimides. More recently, Nájera’s group [ 55 , 56 ] studied the reaction employing several chiral 1,2-diamines as catalysts, while Kokotos used different α- or β-amino acids as organocatalysts in the presence of CsCO 3 [ 57 ]. Finally, Nugent [ 58 , 59 ] examined the use of isoleucine or threonine as organocatalyst in the presence of a hydrogen bond donor (sulfamide) and a base (4-dimethylaminopyridine, DMAP) ( Figure 1 ).…”

Guanidines from ‘toxic substances’ to compounds with multiple biological applications – Detailed outlook on synthetic procedures employed for the synthesis of guanidines

“…[165] A systematic survey of basic /nucleophilic organocatalysts for the polyaddition in bulk of polyols, PEG-600, and PTMO-650 to isophorone diisocyanate (IPDI), has been performed by Landais et al in 2012. Guanidines were shown to be very efficient catalysts for the urethane linkage formation.…”