THE ZETA (ZETA) EFFECT OF TIN

cis,trans,cis-6-(Trimethylstannyl)-2-decalyl tosylate (5-OTs) was prep ared in order to test whether tin can assist in the formation of a car bocation over six bonds (a zeta effect). This system has the requisite diequatorial (zigzag) arrangement of nucleofuge and electrofuge to gi ve rise to triple hyperconjugation. Comparisons were made with the axi al-equatorial trans,trans,cis isomer (6-OTs) and with the analogous eq uatorial and axial decalin systems lacking the tin group (7-OTs and 8- OTs). The diequatorial system 5-OTs did not show a rate acceleration i n comparison with the models, and its rate was sensitive to solvent nu cleophilicity. Products for both 5 and 6 were substitution with invers ion and elimination. These observations indicate that tin does not ass ist in positive charge development over six bonds.