Reagent application homogeneous

In addition to the insoluble polymers described above, soluble polymers, such as non-cross-linked PS and PEG have proven useful for synthetic applications. However, since synthesis on soluble supports is more difficult to automate, these polymers are not used as extensively as insoluble beads. Soluble polymers offer most of the advantages of both homogeneous-phase chemistry (lack of diffusion phenomena and easy monitoring) and solid-phase techniques (use of excess reagents and ease of isolation and purification of products). Separation of the functionalized matrix is achieved by either precipitation (solvent or heat), membrane filtration, or size-exclusion chromatography [98,99]. 

The chromatogram is freed from mobile phase, immersed in the dipping solution for 3 s or homogeneously sprayed with the spray solution and then dried in a stream of cold air. Triazines must be converted to chlorinated derivatives by exposing the chromatogram to chlorine gas (see Procedure Tested ) before application of the reagent. 

Catalyst-mediated decomposition of diazo compounds in the presence of C=S compounds has found application for the preparation of thiiranes in homogeneous systems (68,110,111). Recently, a convenient procedure for the preparation of geminal dichlorothiiranes from nonenolizable thioketones and chloroform under Makosza conditions was reported (112). Another approach to 2,2-dihalogenated thiiranes (e.g., 2,2-difluoro derivatives) involves the thermolysis of Seyferth reagents in the presence of thioketones (113,114a). Nucleophilic dimethoxycarbene was shown to add smoothly to adamantanethione to provide a unique approach to a thiiranone (5, 5 )-dimethylacetal (114b). 

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