PREPARATION OF METHYL CARBAMATES FROM PRIMARY ALKYLCARBOXAMIDES AND ARYLCARBOXAMIDES USING HYPERVALENT IODINE

A series of 14 primary alkyl- and arylcarboxamides were treated with PhI(OAc)2 in KOH-CH3OH at 5-10-degrees-C to give the corresponding methyl carbamates in good to excellent yields. These conditions avoid the use of elemental bromine or heavy metal reagents (Pb(OAc)4, AgOAc, Hg(OAC)2), while taking advantage of the commercial availability of PhI(OAc)2. The methyl carbamates are easily purified via column chromatography on silica gel. The isolated yields of the carbamates ranged from 72 % for methyl N-cyclopropylcarbamate to 97 % for methyl N-phenylcarbamate.