A short synthesis of (+)-harzialactone A and (R)-(+)-4-hexanolide via proline-catalyzed sequential α-aminooxylation and Horner–Wadsworth–Emmons olefination of aldehydes

Organocatalyzed Asymmetric α-Oxidation, α-Aminoxylation and α-Amination of Carbonyl Compounds

“…Other target molecules which had been successfully synthesized using proline catalyzed α-aminoxylation as one of the key steps include halipeptin A [ 104 ], (+)- exo - and (–)- endo -brevicomins [ 105 ], linezolid and eperezolid [ 106 ], levetiracetam [ 107 ], ( S , S )-ethambutol [ 108 ], (+)-harzialactone A and ( R )-(+)-4-hexanolide [ 109 ], ( R )-seleginine [ 110 ], ( S )-propanolol and ( S )-naftopidil [ 111 ], (+)-disparlure and its trans -isomer [ 112 ], (-)-anisomycin [ 59 ] and (1 R ,3 S )-thysanone, a HRV 3C-protease inhibitor [ 113 ].…”

First chemo-enzymatic synthesis of the (R)-Taniguchi lactone and substrate profiles of CAMO and OTEMO, two new Baeyer–Villiger monooxygenases

“…The optical purity of lactones 13b , 15b was much higher than previously published values [ 13b  = 94% (−) vs 63% (−) and 15b  = 92% (+) vs 73% (+)]. These lactones are important intermediates for the synthesis of tricyclic benzomorphan analogs, (+)-harzialactone A, chiral tricyclic amines [38–40], and for the synthesis of lignans such as enterolactone, hinokinin, arctigenin [41], the synthesis of optically pure gosmin A and schizandrin [42]. In all cases, OTEMO had the same stereopreference as CAMO, but was less stereoselective.…”

Recent Advances on the Organocatalyzed Enantioselective α-heterofunctionalization of Carbonyl Compounds

“…For instance, (S,S)-ethambutol (23) [26], (R)-selegiline (24) [27] and (-)-anisomycin (27) [30], which could be alternatively synthesized by means of an organocatalyzed α-amination reaction (see section 2.2, Figure 2), could be prepared with similar results by using this transformation. In a similar way, the antiinflammatory halipeptin A (111) [94], the antitumor agents tarchonanthuslactone (112) [95], (+)-cytotrienin A [96] and (+)-harzialactone A and (R)-(+)-4-hexanolide [97], the antibacterials linezolid (113) and eperezolid [98], the antiepileptic drugs levetiracetam (114) [99], the pheromones (-)-endo-brevicomin (115) [100], (+)-disparlure [101] and (2S,3S)-2-hydrohyhexylcyclopentanone [102], and the enzyme inhibitors (+)-panephenanthrin (116) [103], and the β-adrenergic blockers (S)-propranolol (117) and (S)-naftopidil [104] have been synthesized using in all cases the α-aminoxylation of aldehydes as a key step (Figure 12). …”