A stereoselective approach to optically active butenolides by Horner–Wadsworth–Emmons olefination reaction of α-hydroxy ketones

Di- and trisubstituted butenolides and tricyclic unsaturated lactones, of high enantiomeric excess were prepared via the efficient sequential esterification Horner–Wadsworth–Emmons reaction of enantiomerically enriched 2-hydroxy-substituted phenones and aromatic cyclic α-hydroxy ketones in good yield.

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(S)-(+)-5-Methyl-4-phenylfuran-2-(5H)-oneC11H10O2Ee >99%[α]D20=+200 (c 0.35, CHCl3)Source of chirality: (S)-(−)-2-hydroxy-1-phenyl-1-propan-1-oneAbsolute configuration: (S)

(S)-(+)-5-Ethyl-4-phenylfuran-2-(5H)-oneC12H12O2Ee = 94%[α]D20=+160 (c 0.45, CHCl3)Source of chirality: (S)-(−)-2-hydroxy-1-phenyl-1-butan-1-oneAbsolute configuration: (S)

(S)-(+)-5-Propyl-4-phenylfuran-2-(5H)-oneC13H14O2Ee = 84%[α]D20=+148 (c 0.15, CHCl3)Source of chirality: (S)-(−)-2-hydroxy-1-phenyl-1-pentan-1-oneAbsolute configuration: (S)

(S)-(+)-4,5-Diphenylfuran-2-(5H)-oneC16H12O2Ee = 74%[α]D20=+101 (c 0.1, CHCl3)Source of chirality: (S)-(+)-2-hydroxy-1,2-diphenyl-ethanoneAbsolute configuration: (S)

(S)-(−)-3a,4,5,6-Tetrahydro-2H-benzo[3,4]cyclohepta[1,2-b]furan-2-oneC13H12O2Ee = 83%[α]D20=-187 (c 0.17, CHCl3)Source of chirality: (S)-(+)-6,7,8,9-tetrahydro-6-hydroxy-5H-benzocyclohepten-5-oneAbsolute configuration: (S)

(R)-(+)-8a-Methyl-8,8a-dihydro-2H-inden[2,1-b]furan-2-oneC12H10O2Ee = 94%[α]D20=+14.0 (c 0.2, CHCl3)Source of chirality: (R)-(+)-2-hydroxy-2-methyl 1-indanoneAbsolute configuration: (R)

(S)-(−)-1-Methyl-2-oxo-2-phenylethyl(diethoxyphosphoryl)acetateC15H21O6P[α]D20=-30.1 (c 2.8, CHCl3)Source of chirality: (S)-(−)-2-hydroxy-1-phenyl-1-propan-1-oneAbsolute configuration: (S)

(S)-(−)-1-Benzoylpropyl(diethoxyphosphoryl)acetateC16H23O6PEe = 93%[α]D20=-16.6 (c 0.2, CHCl3)Source of chirality: (S)-(−)-2-hydroxy-1-phenyl-1-butan-1-oneAbsolute configuration: (S)

(S)-(−)-1-Benzoylbutyl(diethoxyphosphoryl)acetateC17H25O6PEe = 85%[α]D20=-11.7 (c 0.17, CHCl3)Source of chirality: (S)-(−)-2-hydroxy-1-phenyl-1-pentan-1-oneAbsolute configuration: (S)

(S)-(+)-2-Oxo-1,2-diphenylethyl(diethoxyphosphoryl)acetateC20H23O6PEe = 82%[α]D20=+73.5 (c 0.21, CHCl3)Source of chirality: (S)-(+)-2-hydroxy-1,2-diphenyl-ethanoneAbsolute configuration: (S)

(+)-2-Oxo-1,2-diphenylethyl-2-(diethoxyphosphoryl) propanateC21H25O6PEe = 75% (major isomer), 85% (minor isomer)[α]D20=+78.2 (c 1.28, CHCl3)Source of chirality: (S)-(+)-2-hydroxy-1,2-diphenyl-ethanone

(S)-(−)-5-Oxo-6,7,8,9-tetrahydro-5H-benzo[7]annulen-6-yl 2-(diethoxyphosphoryl)acetateC17H23O6P[α]D20=-2.05 (c 1.4, CHCl3)Source of chirality: (S)-(+)-6,7,8,9-tetrahydro-6-hydroxy-5H-benzocyclohepten-5-oneAbsolute configuration: (S)

(R)-(−)-2-Methyl-1-oxo-2,3-dihydro-1H-inden-2-yl 2-(diethoxyphosphoryl)acetateC16H21O6PEe = 69%[α]D20=-15.0 (c 0.5, CHCl3)Source of chirality: (R)-(+)-2-hydroxy-2-methyl 1-indanoneAbsolute configuration: (R)