Application of asymmetric phase-transfer catalysis in the enantioselective synthesis of cis-5-substituted proline esters

Asymmetric Ruthenium‐Catalyzed Hydroalkylation of Racemic Allylic Alcohols for the Synthesis of Chiral Amino Acid Derivatives

“…[27] In addition, 5 a could undergo oxidation, hydrolysis, and hydrogenation reactions to produce 12 via intermediate 10. [19] And 13 could be prepared from 5 a' according to the procedures reported by Wade and co-workers. [19] Preliminary mechanistic studies were carried out to elucidate the reaction pathway.…”

“…[19] And 13 could be prepared from 5 a' according to the procedures reported by Wade and co-workers. [19] Preliminary mechanistic studies were carried out to elucidate the reaction pathway. Based on our previous studies, the chiral Ru-diamine-diphosphine catalyst could dehydrogenate the allylic alcohol to afford an α,β-unsaturated ketone intermediate, e.g.…”

Bifunctional Thio/Squaramide Catalyzed Stereoselective Michael Additions of Aldehydes to Nitroalkenes towards Synthesis of Chiral Pyrrolidines

“…Chiral 2,3‐disubstituted pyrrolidines were also prepared by cyclization reaction of enamines generated from butanedial and various protected imines . Highly stereoselective synthesis of cis ‐5‐substituted proline esters consists of an asymmetric PTC Michael addition, followed by acid‐catalyzed imine exchange and catalytic hydrogenation …”

Efficient synthesis of unnatural dipeptides based on cis-2,5-disubstituted pyrrolidine

“…The synthesis of several indolizidine alkaloids containing a chiral trans-2,5-disubstituted pyrrolidine moiety was described (Dhimane et al 1997;Takahata et al 1990;Wang et al 1999;Lee et al 2000;Cahill et al 1999); however, only few methods provide stereoselective synthesis of cis-2,5-disubstituted pyrrolidine derivatives (Haddad et al 1998;Brenneman and Martin 2004;Bagley and Tovey 2001;Colandrea et al 2006). Lygo et al (2010) have described a synthetic route to cis-2,5-disubstituted pyrrolidine derivatives by asymmetric phase-transfer catalysis. Previously, we have reported a facile access to enantiopure cis-2,5-disubstituted pyrrolidines (Fig.…”