(4-Phenyl-but-3-ynyl)-carbamic acid tert-butyl ester → cis-4-Phenyl-but-3-enylamine

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Reaction Steps

A suspension of palladium on barium sulfate (15 mg) was stirred for 15 min in 1 mL pyridine. (4-phenyl-but-3-ynyl)-carbamic acid tert-butyl ester (66 mg) was added and the solution was purged with hydrogen then stirred for 1 h under a hydrogen-filled balloon. The solution was diluted with ethyl acetate (10 ml) and washed 3 times with 1 N hydrochloric acid (10 ml). The ethyl acetate layer was dried over sodium sulfate and filtered. The filtrate was evaporated and the resulting residue (54 mg) is primarily cis-(4-phenyl-but-3-enyl)-carbamic acid tert-butyl ester along with (4-phenyl-but-3-ynyl)-carbamic acid tert-butyl ester, 4-phenylbutylamine, and trans-(4-phenyl-but-3-enyl)-carbamic acid tert-butyl ester. The combined minor products constitute ˜20% of the crude material. The tert-butoxycarbonyl group of the desired product was removed by Procedure P to give cis-4-phenyl-but-3-enylamine, which was used in subsequent transformations without further purification.

Provenance & Evidence