Dichlorocarbene, reactions

The mechanism of this dichlorocarbene reaction has been thoroughly investigated. Plancher s claim to have converted 2//-pyrroles (14) to chloro-pyridines (15)22,23 was shown to be inaccurate.31 32 Although 14 could be... 

Polymer-supported podands appear to be more commonly used in solid-liquid systems. A variety of chemical transformations including nucleophilic substitutions at saturated carbon atoms [214,215], esterifications [214], sodium bo-rohydride reduction [214], fluoride-catalyzed Michael addition [214], phenacyl ester synthesis, Darzen s reaction, Wittig alkenylation, and dichlorocarbene reactions can be carried out under these conditions [214],... 

The NMR spectroscopy results testify the double bonds dichlorocyclopropanation both in the main ehain and side chains of polydiene macromolecules (Scheme 8). Cis-and trans-double bonds in the 1,4-addition units [48] are more active in the dichlorocarbene reaction. 

One example of the reaction of dichlorocarbene with a tertiary amine under phase transfer conditions has been reported [20]. 5,7-Diphenyl-1,3-diazaadamantan-6-one is transformed into l,5-diphenyl-N,N-diformylbispidin-9-one in 23% yield. This unusual reaction may be rationalized as follows. Coordination of dichlorocarbene with a nitrogen lone pair yields a zwitterion (VI). Neighboring nitrogen assists fragmentation and the iminium zwitterion VII results. Protonation and hydrolysis of VII followed by dichlorocarbene reaction with the resulting secondary amine yields the bis-formamide VIII. The sequence is formulated in equation 3.13. 

Thus far, there is only one dichlorocarbene reaction with a thioether reported [25]. Dichlorocarbene reacts with the allylic sulfide to form an ylid which undergoes a facile [2, 3] sigmatropic rearrangement. The product obtained after hydrolysis and chromatography is a mixture of /3,7-unsaturated-S-phenyl esters according to equation 3.17. 

The activity of the polymeric salts as catalysts in phase transfer reactions was tested in alkylation and dichlorocarbenation reactions carried out on chiral or prochiral substrates under polyphase conditions in the presence of concentrated aqueous sodium hydroxide. They were tested also in oxidation reaction of racemic alcohols under acidic conditions. ... 

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