Navigation

0 Hits

  • Previous / Next

You are using Science Of Synthesis as a Guest.
Please login to access the full content or check if you have access via
46.5.3.1.3 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]

Meeeee 88 Meeeee-Meeeeeeee Meeeeeeeeee ee 8,8-Meeeeeee-8,8-ee(eeee-8­ee-8-ee)-8,8-eeeeeeeee eeeeeee Meeeeeeeeeeeeee[‌888‌]

Meeeeeee eeeeeee eeee eeeeeee eeeeeeee eeeeeeeeeeee eee ee eeee ee eeeeeee eeee eeee eee(η8-eeeeeeeee-8,8-eeeee)eeeeee(8) eeee eeeeeeeee eeeeeee ee eeeeeeeee eee eeeeeeeeee ee e eeeee eeee e eeeeeee eeeee eeee eeeeeeeeee eeee ee eeeeeeeee ee ee eeeeeeee eeeeeeee ee eee eeeeeeeeee. Mee eeeeeee, ee eee eeeeeeee ee eeeeeeeeeeee, eee(η8-eeeeeeeee-8,8-eeeee)eeeeee(8), eee eeeeeee 888, eeeeeeee 8,8-eee(eee-8-eeee)eeeeeeee (88) ee eeeeeeee ee eeeeee eee eeeeeeeeeeeee eeeeeeeee eeeeeeeeee-8,8-eeeee 888 ee 88% eeeee (Meeeee 88). Meeee eeeeeee eeeeeeeeee 8,8-eeeeee eeeeeee eee eeeeeeeeeee eeeeeeeeee eeeeeee eeeeeeeeeeeeeeeee.[‌88‌]

Meeeee 88 Meeeee-Meeeeeeee Meeeeeee eeeeeee Meeeeeee 8,8-Mee(eee-8-eeee)eeeeeeee eee Meeeeeeeeeee[‌88‌]

Meeeeeeeeeee Meeeeeeee

Meeeeeee 8-Meeeeeeeee-8-(8-eee-8-eeeeeeeeeeee-8-eeeeeee)eeeeeeeeeeee-8,8-eeeeeeee­eeeee (888); MeeeeeeMeeeeeeee:[‌88‌]

M eeee ee Me(eee)8 (8.8ee, 8.888eeee) eee eee eeeeeee 888 (88.8ee, 8.88eeee) ee eeeeeee (8eM) eee eeeeeee eee 8e ee e eeeeeeee, eee eeee eeeee ee eeeeeeee 8,8-eee(eee-8-eeee)eeeeeeee (88; 888.8ee, 8.88eeee) eee MeMMM (88.8ee, 8.88eeee) ee eeeeeee (8.8eM). Mee eeeeeee eee eeeeeee eee 8e ee ee, eeeeee ee eee eeeeeeeeeeee eee eee eeeeeee eee eeeeeeee ee eeeeee eeeeeeeeeeeeee (eeeeee eee); eeeee: 888ee (88%).

References


Cookie-Einstellungen