Reaction #40600

Reaction equation

salvinorin B

(2S,4aS,6aR,7R,9S,10aS,10bR)-9-(hydroxy)-2-(3-furanyl)dodecahydro-6a,10b-dimethyl-4,10-dioxo-2H-naphtho[2,1-c]pyran-7-carboxylic acid methyl ester

triphenylphosphine

bromoform

triphenylphosphine

bromoform

→

36

Yield 59.0%

(2S,4aS,6aR,7R,9R,10aS,10bR)-9-(Bromo)-2-(3-furanyl)-dodecahydro-6a,10b-dimethyl-4,10-dioxo-2H-naphtho[2,1-c]pyran-7-carboxylic acid methyl ester

Yield 59.0%

Solvents

CH2Cl2

Conditions

Workup

1. 1
   workup.WAITwas still present after 16 h
2. 2
   workup.STIRRINGthe mixture was stirred for an additional 3 h
3. 3
   OtherThe solvent was removed under reduced pressure
4. 4
   Otheraffording a crude solid
5. 5
   OtherThe oil was purified by column chromatography (eluent: 30% EtOAc/n-hexanes)

Procedure

A mixture of salvinorin B (8a) (0.15 g, 0.38 mmol), triphenylphosphine (0.21 g, 0.80 mmol), and bromoform (0.15 g, 0.45 mmol) in CH2Cl2 (30 mL) was stirred at room temperature overnight. TLC indicated that starting material was still present after 16 h, thus additional triphenylphosphine (0.11 g, 0.42 mmol) and bromoform (0.07 g, 0.21 mmol) were added and the mixture was stirred for an additional 3 h. The solvent was removed under reduced pressure affording a crude solid. The oil was purified by column chromatography (eluent: 30% EtOAc/n-hexanes) to afford 0.10 g (59%) of 36 as a white solid, mp 170-173° C. (EtOAc/n-hexanes); 1H NMR (CDCl3): δ 1.15 (3H, s); 1.48 (3H, s); 1.60 (3H, m); 1.81 (1H, dd, J=2.7, 9.9); 1.95 (1H, dd, J=13.2, 26.1); 2.1 (2H, m); 2.27 (1H, s); 2.47 (1H, dd, J=4.8, 13.2); 2.66 (1H, m); 2.80 (1H, dd, J=3.3, 13.2); 3.70 (3H, s); 3.89 (2H, d, J=2.4); 4.45 (1H, m); 5.55 (1H, dd, J=4.8, 11.7); 6.38 (1H, dd, J=0.9, 1.5); 7.4 (2H, m).

Source