Pyridine → HCID 69285638, compound

Participants

Reaction Steps

A solution of [(1S,2R,4R)-(4-hydroxy-2-propenyl-cyclohexyl)]-carbamic acid benzyl ester as a colorless oil (0.56 g, 1.9 mmol) in CH2Cl2 (20 mL) was charged with pyridine (0.8 mL, 9.5 mmol) and Dess-Martin Periodinane (0.9 g, 2.1 mmol). The reaction was stirred at RT for 12 h and concentrated in vacuo. Purification of the residue via flash chromatography afforded the desired [(1S,2R)-(4-oxo-2-propenyl-cyclohexyl)]-carbamic acid benzyl ester (0.37 g) as a 3:1 mixture of Z and E diastereomers. This material was dissolved in titanium tetraisopropoxide (2 mL) and N-methylisopropylamine (3 mL) with agitation. The resultant solution was stirred for 1 h at RT and then charged with MeOH (6 mL) and sodium borohydride (100 mg; added slowly—vigorous gas evolution was observed). The reaction was stirred for 1.5 h and then quenched with 0.2 N NaOH. The resultant mixture was diluted with CH2Cl2 and stirred vigorously before being filtered through Celite. The phases were separated and the organic phase was washed with brine, dried (MgSO4), filtered, and concentrated in vacuo to give the desired [(1S,2R,4R)-4-(isopropyl-methyl-amino)-2-propenyl-cyclohexyl]-carbamic acid benzyl ester (295 mg, mixture of olefin diastereomers, some 4S diastereomer present) as a light yellow oil. MS found: (M+H)+=345.31.

Provenance & Evidence