Reactions of t-Boc-Protected Amines with Difluorocarbene

The reactions of t-Boc-protected secondary and primary amines with difluorocarbene generated from trimethylsilyl (fluorosulfonyl) difluoroacetate [ Me3SiOC(O) CF2SO2F] (TFDA) in toluene at 110 degrees C results in the replacement of t-Bu by difluoromethyl in the t-Boc group. This reaction can be carried out in the presence of CH2Br and COOMe moieties in the structure of the protected amine. In the example of a tBoc- protected amine containing a C= C double bond, replacement of the t-Bu group and/or cyclodifluoropropanation takes place. Difluoromethyl esters are shown to react with primary and secondary amines yielding the corresponding ureas.