WEISS-COOK CONDENSATIONS INVOLVING UNSATURATED AND TRANSANNULARLY ALKYLATED CYCLODODECANE-1,2-DIONES

(Z)-Cyclododec-7-ene-1,2-dione (4), its alkyne equivalent 7, and the s tructurally related propellane 14 have been subjected to condensation with dimethyl 1,3-acetonedicarboxylate. The alpha-diketones 4 and 7 un dergo the Weiss-Cook condensation normally to deliver diquinane produc ts in high yield. The sterically congested 14 showed no tendency to re act. The underlying cause of the parallelism between eight- and twelve -membered rings and the contrasting behavior of cyclodecyl analogs is evaluated in terms of thermodynamic versus kinetic control.