And phase transfer catalysis

With the discovery of the crowns and related species, it was inevitable that a search would begin for simpler and simpler relatives which might be useful in similar applications. Perhaps these compounds would be easier and more economical to prepare and ultimately, of course, better in one respect or another than the molecules which inspired the research. In particular, the collateral developments of crown ether chemistry and phase transfer catalysis fostered an interest in utilizing the readily available polyethylene glycol mono- or dimethyl ethers as catalysts for such reactions. Although there is considerable literature in this area, much of it relates to the use of simple polyethylene glycols in phase transfer processes. Since our main concern in this monograph is with novel structures, we will discuss these simple examples further only briefly, below. 

Dietrich, Lehn and Sauvage recognized not only the possibility of enclosing a cation completely in a lipophilic shell, but they also recognized the potential for using such systems for activating associated anions. This is made particularly clear in a paper which appeared some years later One of the original motivations for our work on cryptates rested on their potential use for salt solubilization, anion activation and phase transfer catalysis . This particular application is discussed below in Sect. 8.3. 

Mathias, L. J. Carraher, C. E., Eds. Crown Ethers and Phase Transfer Catalysis in Polymer Science Plenum Press, New York,... 

Allyl chlorides and bromides are readily carbonylated to unsaturated acids using nickel cyanide and phase transfer catalysis conditions. Mechanistic studies revealed that the key catalytic species in this reaction is the cyanotricarbonylnickelate ion(20). 

See Symposium on Crown Ethers and Phase Transfer Catalysis in Polymer Chemistry , Polym. Prepr., Am. Chem Soc., Div. Polym. Chem. 1982, 23(1), 139-192 and references therein. 

L. J. Mathias, Crown ethers and phase transfer catalysis in polymer chemistry, J. Macromol. Sci., Chem.,... 

The principles underlying the N- alkylation of indoles are the same as those for pyrroles (67T3771). Development of synthetic techniques for maximizing yields has resulted in procedures using dipolar aprotic solvents, crown ether and phase transfer catalysis, as well as reactions in liquid ammonia. These techniques are illustrated by some representative examples given in Table 8. 

A. Loupy, A. Petit, D. Bogdal, Microwave and Phase-Transfer Catalysis. In Microwaves in Organic Synthesis, A. Loupy (Ed.), Wiley-VCH, Weinheim, 2002. 

Micelles and Phase-transfer Catalysis in Substitution Reactions. 255... 

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