D. Llerena et al., SYNTHESIS OF VARIOUSLY SUBSTITUTED ALLENEDIYNES AND THEIR COBALT (I)-MEDIATED [2+2+2] CYCLOADDITION REACTIONS, Tetrahedron, 54(32), 1998, pp. 9373-9392
Syntheses of variously substituted allenediynes where the allene moiet
y is at the terminal or internal position are described. Their cobalt(
I)-mediated [2+2+2] cycloaddition reactions led to the corresponding e
ta(4)-complexed tricyclic compounds; the regioselectivity of these cyc
lizations depending on the substitution and the position of the allene
is discussed. (C) 1998 Elsevier Science Ltd. Ali rights reserved.