1 The Basic Principle of Phase - Transfer Catalysis and Some Mechanistic Aspects
نویسندگان
چکیده
In 1971, Starks introduced the term phase-transfer catalysis to explain the critical role of tetraalkylammonium or phosphonium salts (QþX ) in the reactions between two substances located in different immiscible phases [1]. For instance, the displacement reaction of 1-chlorooctane with aqueous sodium cyanide is accelerated many thousand-fold by the addition of hexadecyltributylphosphonium bromide 1 as a phase-transfer catalyst (Scheme 1.1). The key element of this tremendous reactivity enhancement is the generation of quaternary phosphonium cyanide, which renders the cyanide anion organic soluble and sufficiently nucleophilic.
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