Survey of Progress in Chemistry

In the general area of organic synthesis, the traditional importance of homogeneous mediums for carrying out reactions is being challenged effectively by a novel approach of conducting reactions in two-phase systems. This method, which is based on the use of heterogeneous, mainly liquidliquid systems, is applicable to a wide range of synthetic problems in which organic substrates react with organic or inorganic anions and with many carbenes. Such reactions are truly numerous and include such well-known processes as nucleophilic aliphatic substitution with inorganic anions, alkylation of organic anions (carbanions and heteroanions), acylation of organic and inorganic anions, oxidation and reduction with anionic agents, condensation of carbanions with numerous electrophilic compounds, generation and reactions of dihalocarbenes and other carbenes, and even some reactions characteristic of organometallic compounds. The success of two-phase methods, illustrated by their general applicability as well as by their simplicity and effectiveness, will be the subject of this chapter.