MEDIUM-SIZED GERMANIUM HETEROCYCLES - FIRST SYNTHESIS AND CONFORMATIONAL-ANALYSIS OF A STERICALLY HINDERED 8-MEMBERED 12H-DIBENZO[D,G][1,3,2]DIOXAGERMOCIN

The first reported synthesis, characterization, and conformational ana lysis of the eight-membered germocin 2,2'-(4,6-di-(1)BuC(6)H(2)O)(2)Ge Me(2) (3) is described. The VT H-1 NMR, C-13{H-1} NMR, and crystallogr aphic data of 3 is consistent with a boat-chair conformation for the r ing in both solution and the solid state. The free energy of activatio n (Delta G(299)) for ring inversion is 55.6 kJ . mole(-1) (13.3 cal . mole(-1)).