Functions Containing One Halogen and Three Other Heteroatom Substituents

Abstract

These functional groups have been prepared by one of three approaches: first, the halogenation of the triheteroatom-substituted methane derivatives to give the product halo triheteroatom-substituted methanes; second, the nucleophilic displacement of halogens from halogenated methane compounds by heteroatom-substituted nucleophiles; and third, halogen exchange of one halogen for the other in halo triheteroatom-substituted methanes. For example, halo orthoformates and halo thio-orthoformates are prepared by the first method of halogenation of the corresponding orthoformates and thio-orthoformates, respectively. The second method of nucleophilic displacement, for example, with two equivalents of trialkylphosphites on trichloromethylisocyanate gave the chloro diphosphonylmethyl isocyanates. The third approach of halogen exchange is well known in the conversions of one halo thio-orthoformate into another halo thio-orthoformate. The heteroatoms could be a part of cyclic (1,3-dithiane, diazirine, etc.) or acyclic systems and in the case of heteroatoms being sulfur, nitrogen, or phosphorus could be in different oxidation states, like sulfide, sulfoxide, sulfone, amino, nitro, azide, phosphonium, phosphonate, etc. When the functional group has a metal as part of the heteroatom substituent, the introduction of the metal has been either via deprotonation using strong bases like alkyl lithiums on halo diheteroatom-substituted methanes or via metal–halogen exchange using organometallics on dihalo diheteroatom-substituted methanes.