ACTIVATION OF A DIENEDIYNE MODEL OF NEOCARZINOSTATIN CHROMOPHORE THROUGH AN ACID-MEDIATED SOLVOLYSIS - EVIDENCE FOR A NEW CYCLIZATION MODE OF ENYNE[3]CUMULENES
Sw. Scheuplein et al., ACTIVATION OF A DIENEDIYNE MODEL OF NEOCARZINOSTATIN CHROMOPHORE THROUGH AN ACID-MEDIATED SOLVOLYSIS - EVIDENCE FOR A NEW CYCLIZATION MODE OF ENYNE[3]CUMULENES, Tetrahedron letters, 34(41), 1993, pp. 6549-6552
When treated with 0.1 equiv. of triflic acid, a solution of the Z-conf
igurated dienediyne 19 in a 2:3 mixture of tert-BuSH and CH2Cl2 furnis
hed the brightly yellow enyne[3]cumulene 20 through a S(N)''-reaction.
20 reacted at room temperature through a Saito-Myers cyclization to t
he substituted styrenes 31 and 24 and through an unprecedented cyclois
omerization to the anthracene 25.