Silyl-protected 1,3-Dipoles

Some amino- and thiomethylsilanes are known to serve as equivalents of azo-methine and thiocarbonyl ylides [577]. Recent examples of the use of organosi-lanes as protected 1,3-dipoles have been reported by Komatsu and by us. 

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In the course of our study on the preparation and [3-1-2] cycloadditions of silyl-protected 1,3-dipoles [581] we succeeded in generating carbonyl ylides 156 by CsF-pro-moted 1,3-eliminationofchloromethyl a-trimethylsilylbenzyl ethers (Scheme 10.223) [582]. The carbonyl ylides react smoothly with a variety of alkenes, alkynes, allenes, and heterodipolarophiles to give five-membered cyclic ethers in good to high yields. 

Silyl-protected stable 1,3-dipole equivalents in cycloaddition reactions leading to N-, S-, or (9-heterocycles 04BCJ835. 

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