C. Boss et R. Keese, DIASTEREOSELECTIVE SYNTHESIS OF CYCLODODECA-1,6-DIALLENES (=CYCLODODECA-1,2,6,7-TETRAENES), Helvetica Chimica Acta, 80(2), 1997, pp. 414-420
The synthesis of substituted cyclododeca-1,6-diallenes (= cyclododeca-
1,2,6,7-tetraenes) from cyclododeca-5,11-diyne-1,4-diols is described
(Schemes 1 and 3). The ca. 1:1 mixtures of the stereoisomers of the cy
clododeca-1,6-diallenes were formed in high yields from the ca. 1:1 di
astereoisomer mixtures of the 1,4-disubstituted cyclododeca-5,11-diyne
s by reactions with Me(2)CuLi or t-BuMgCl/(CuI)-I-1. In mechanisticall
y relevant experiments with the pure diastereoisomers of 1,4-dimethylc
yclododeca-5,11-diyne-1,4-diol, it is demonstrated that the configurat
ion is conserved in these reactions. The first synthesis of a 1-substi
tuted cyclododeca-2,8-diyne bearing only one propargylic leaving group
gives access to a mixed 12-membered allen-yne (Scheme 5).