反应详情

By the method of Preparation 3 a), tert-butyl (3R)-3-({[(1S)-2,2-dimethyl-1-(benzyloxycarbonyl)propyl]amino}carbonyl)hex-5-enoate (2.085 g, 5.0 mmol) was reacted with 4-iodo-1-(3-methoxyphenyl)-2-methylbenzene (Preparation 20) (889 mg, 2.13 mmol) under palladium catalysis, using N-ethylmorpholine as base at reflux in acetonitrile for 14.5 h. Work-up as before followed by purification by flash chromatography (hexane:ethyl acetate=10:1) gave mainly tert-butyl (3R,5E)-3-({[(1S)-2,2-dimethyl-1-(benzyloxycarbonyl)propyl]amino}carbonyl)-6-(3′-methoxy-2-methylbiphen-4-yl)hex-5-enoate as a pale yellow gum (1.043 gm, 80%). 1H nmr suggested that two alkene isomers, the (5Z) and (4E) were also present. The mixture of alkenes was taken onto the next step (see b, below).

1. custombefore followed by purification by flash chromatography (hexane:ethyl acetate=10:1)