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Please login to access the full content or check if you have access via Variation 3: Nickel-Catalyzed Cyclization of Diynes

DOI: 10.1055/sos-SD-046-00090

Gandon, V.; Thorimbert, S.; Malacria, M.Science of Synthesis, (200946212.

Nickel(0) and nickel(I) complexes can be used in the intramolecular cyclizations of diynes and, depending upon the conditions (ligands, additives, other reagents, etc.), monocyclic or bicyclic 1,3-dienes are isolated.[‌84‌,‌121‌‌123‌] A phosphinylated cross-linked polystyrene may also be employed, which allows better yields and selectivities than if the corresponding unsupported catalytic system is utilized.[‌124‌] The nickel(0)-catalyzed hydrosilylations of octa-1,7-diynes afford 1,2-bis(alkylidene)cyclohexanes in which the silylated alkylidene component is Z configured. Such cyclizations are efficient and can be performed using mono-, di-, or trialkoxysilanes, monoaminosilanes, or trialkylsilanes. An example of this type is shown in Scheme 47 in which the diyne 140 is converted into the silylated (3aR*,7aR*)-2,2-dimethyl-5,6-bis(methylene)hexahydro-1,3-benzodioxole 141, as the major product, in 73% yield.[‌121‌]

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