Derivatives of pentacyclo [6.2.1.1 (3,6).0(2,7).0(4,10)] dodecane (or half-
cage hydrocarbon) were investigated at the 6-31G* level. Bond lengths and a
ngles as well as charge distributions in conformers of the "outside" alcoho
l reveal the importance of hyperconjugation of the lone pair on oxygen with
suitably oriented neighboring carbon or hydrogen atoms. These alcohols may
serve as sensitive probes for electrostatic effects owing to hydroxyl grou
ps and thus for lone pair directionality, (C) 1999 Elsevier Science B.V. Al
l rights reserved.