LONG-RANGE EFFECTS OF THROUGH-BOND ORBITAL INTERACTIONS ON THE DESILYLATION RATE OF SILYL ETHERS

The kinetics of the desilylation reactions of a range of sulfonated an d methoxylated norbornyl silyl ethers 1-10 were investigated to establ ish the quantitative correlation between the geometry of the a-relay a nd the rate of desilylation. These desilylation rates generally decrea se in the order W > sickle-like > U arrangement of the sigma-relay. Th e methoxylated silyl ethers show a decreased reactivity in comparison with the corresponding sulfonated silyl ethers. The orientation of the silyloxy group does not affect the reaction rate. Conformational mobi lity and alkyl substitution of the a-relay also are of influence on th e rate of desilylation. The observed effects are confirmed by similar behavior in the desilylation reactions of the silyl ethers 11-14 deriv ed from transperhydronaphthalene-1,4-diols.