Transamination studies on N-(1-alkenylthio)phthalimides and related compounds. Synthesis of 1-alkenesulfenamides and 1-alkenesulfonamides

In an attempt to develop a method for the general preparation of 1-alkenesulfenamides, some N,N-bis(trimethylsilyl)-1-alkenesulfenamides (4) were converted to a number of nitrogen functionalized analogs through desilylation and acylation procedures. Mono- and dibenzoylated derivatives 5a and 6a did not undergo transamination reactions with simple amines. Transamination reactions could be achieved once compounds 4 were converted to thiophthalimides 7. The transamination products 8 are unstable to chromatography, but could be oxidized to 1-alkenesulfonamides 9 using MCPBA. Some of the sulfenamides 8 may be stable to distillation. 3-(Alkenylthioimino)phthalides 11, isomers of thiophthalimides 7, also react with amines, but the process of ring opening accompanies transamination. It was found that the transamination reactions of 11 probably involve the intermediacy of isomers 7.