1-(Triphenylphosphoranylidene)acetone → {7-Nitro-8-[(E)-3-oxo-1-butenyl]-2,3-dihydro-1,4-benzodioxin-2-yl}methyl4-methylbenzenesulfonate
Reaction equation
[CH3:1][C:2]1[CH:7]=[CH:6][C:5]([S:8]([O:11][CH2:12][C@@H:13]2[O:18][C:17]3[C:19]([CH:26]=O)=[C:20]([N+:23]([O-:25])=[O:24])[CH:21]=[CH:22][C:16]=3[O:15][CH2:14]2)(=[O:10])=[O:9])=[CH:4][CH:3]=1.C1(P(C2C=CC=CC=2)(C2C=CC=CC=2)=[CH:35][C:36](=[O:38])[CH3:37])C=CC=CC=1>C1(C)C=CC=CC=1>[CH3:1][C:2]1[CH:7]=[CH:6][C:5]([S:8]([O:11][CH2:12][CH:13]2[O:18][C:17]3[C:19](/[CH:26]=[CH:35]/[C:36](=[O:38])[CH3:37])=[C:20]([N+:23]([O-:25])=[O:24])[CH:21]=[CH:22][C:16]=3[O:15][CH2:14]2)(=[O:9])=[O:10])=[CH:4][CH:3]=1Participants
4
Procedure
To a solution of 3.00 g (7.37 mmole) of [(2R)-8-formyl-7-nitro-2,3-dihydro-1,4-benzodioxin-2-yl]methyl 4-methylbenzenesulfonate in 250 mL of toluene was added 2.90 g (9.10 mmole) of 1-triphenylphosphoranylidene-2-propanone. The mixture was stirred at room temperature under nitrogen for 5 hours, during which time some product precipitated from solution. The solvent was removed in vacuum and the crude residue was column chromatographed on silica gel with methylene chloride as eluent to give 3.0 g of the (R)-enantiomer of the title compound as a yellow solid. 1H-NMR (CDCl3): doublet 7.8 δ (2 H); doublet 7.6 δ (1 H); doublet 7.5 δ (2 H); doublet 7.4 δ (2 H); doublet 6.95 δ (1 H); doublet 6.6 δ (1 H); multiplet 4.5 δ (1 H); doublet of doublets 4.0 δ (1 H); multiplet 4.2 δ (3 H); singlet 2.45 δ (3 H); singlet 2.4 δ (3 H).