Tetramethyltin → 5-acetyl-3-(N-allyl-N-n-propylamino)chroman

Participants

Reaction Conditions

Reaction Steps

3 -(N-Allyl-N-n-propylamino)-5 -trifluoromethane sulfonyloxychroman (0.28 g, 0.74 mmol), LiCl (0.097 g, 2.3 mmol), PdCl2 (dppf) (0.031 g, 0.04 retool) and 2.6-di- t-butyl- 4-methylphenol (0,005 g) were dissolved in DMF (5.0 mL) in a three-necked round-bottom flask (50 mL) with a magnetic stirrer. The flask was evacuated, followed by inlet of CO (three times). Tetramethyltin (0.12 mL, 0.89 mmol) was added and then the mixture was stirred under an atmosphere of CO (1 arm) at 120° C. (oilbath temp) for 4 hours. The solvent was evaporated, the residue was partitioned between aqueous NH3 (2M) and CH2Cl2 (3×15 mL) and the organic phases were dried (Na2SO4), filtered and concentrated in vacuo. Column chromatography on silica with THF-n-hexane (1:9) as eluent afforded 5-acetyl-3-(N-allyl-N-n-propylamino)chroman (0.078 g, 39% yield) as an oil. The base was precipitated from an ether solution by adding a slight excess of HCl (approx. 3M in ether). The crude salt was collected and dried in vacuo at 40° C. to give a white amorphous powder. Mp 125°-127° C. PdCl 2 (dppf)=dichloro[1,1'-bis(diphenylphosphino)-ferrocene] palladium (II).

Provenance & Evidence