l-Prolinol as a chiral auxiliary in the photochemical synthesis of a new aryltetraline lignan analogue

Recent strategies and tactics for the enantioselective total syntheses of cyclolignan natural products

“…115 To begin the synthesis, a-bromomalonate 199 and aldehyde 200 were treated with organocatalyst 201 to produce the asymmetric cyclopropanation product 202 (Scheme 57). Reduction of diester 202 followed by 116 and adapted their methods for its formal total synthesis in 2016. 117 The key step in their synthetic strategy was the photocyclization of a chiral amide ester to generate the C2-C7 0 bond from a 1,4-diarylbutane synthon (Scheme 58, also refer to similar Scheme 35).…”

“…Czarnocki and coworkers previously developed photocyclization strategies that produced compounds with similar features to podophyllotoxin ( 1 ) 116 and adapted their methods for its formal total synthesis in 2016. 117 The key step in their synthetic strategy was the photocyclization of a chiral amide ester to generate the C2–C7′ bond from a 1,4-diarylbutane synthon (Scheme 58, also refer to similar Scheme 35).…”

Unique cyclolignan’s architecture obtained via acid catalyzed cyclization/intramolecular Friedel-Crafts tandem reaction

“…[7][8][9] Our research group is interested in the stereoselective synthesis of cyclolignans, achieved by photocyclization of chiral bis-benzylidenesuccinates. 10 We found that L-prolinol is an excellent chiral auxiliary 11 and used for the formal synthesis of PPT 12 and the total synthesis of (+)-epigalcatin. 13 We also studied the regioselectivity in the photocyclization of cyclolignan precursors 14 and we used the bis-benzylidenesuccinyl platform as a photolabile protecting group for secondary amines.…”

Highly efficient chiral polydentate sulfinyl ligands/catalysts containing prolinol moiety

“…11 Particularly, prolinol and its various derivatives are commonly applied in asymmetric synthesis. 12 They proved to be valuable auxiliaries 13 and catalysts in the asymmetric formation of carbonecarbon 14 and carbon-heteroatom bonds. 15 Therefore, we decided to replace the amino groups in our original sulfinyl ligands 4 and 5 with one or two prolinol moieties, to obtain new ligands 9 and 10, having four or five potential coordination centers, respectively (Scheme 3).…”