Isonitriles from dichlorocarbene

In a process reminiscent of isonitrile hydrolysis, dichlorocarbene as generated from CHCI3 reacts with HaS in the presence of primary or secondary amines to yield thioformamides (79 equation 37). If pressure is employed, CCI4 or CI3CCCI3 can also be used with the latter giving dithiooxamides (27), e.g. with BuNHa, 65% of BuNHCSCSNHBu. 24... 

Although the extraction of primary amines from a basic medium with chloroform is an inadvisable procedure, on account of the formation of trace amounts of the pungent isonitriles, the specific synthesis of isonitriles by the two-phase reaction of primary amines with chloroform is unreliable. However, the application of the phase-transfer technique [e.g. 1 -5] for the controlled release of dichlorocarbene facilitates the synthesis of isonitriles in relatively high yields (Table 7.12). 

Isonitrile synthesis from primary amines and dichlorocarbene (from chloroform) or dibromocarbene (see 1st edition). 

---