Organoselenium resin

Scheme 11.11. Traceless cleavage from the organoselenium resin.

Traceless cleavage has also been achieved with an organoselenium resin. Resin-bound methyl 2-seleno acrylate reacted with an excess of azomethine yUde at room temperature (Scheme 11.11). N-Acylation of the pyrrolidines gave diverse resin-bound products that were released from the support by oxidative cleavage with hydrogen peroxide. A total of 13 substituted 2,5-dihydro-l//-pyrroles were produced with 57-74% yield. 

A related method based on an organoselenium resin has been applied to the synthesis of a wide variety of nitrogen-containing heterocycles. Reactions of resin-bound alkenes or alkynes with nitrile oxides and azides gave a variety of isoxazolines, isoxazoles, and 1,2,3-triazoles in high yields and purities (Schemes 11.42 and 11.43). ... 

The developed methods were applied to the synthesis of a wide variety of related compounds such as 1,2,4-oxadiazole derivatives (Scheme 11.44) and substituted uracils (Scheme 11.45). The organoselenium resin was also used in the solid-phase synthesis of pyrrolidines from azomethine ylides (Scheme 11.11). ... 

Scheme 11.44. Organoselenium resin in the synthesis of 1,2,4-oxadiazole derivatives.

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