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
2.11.5.B Applications of Product Subclass 5 in Organic Synthesis

DOI: 10.1055/sos-SD-002-00797

Negishi, E.-i.; Takahashi, T.Science of Synthesis, (20032754.

As in Section 2.11.4, there does not appear to have been any reported and recognized reactions of five-membered hafnacycles exhibiting clear-cut advantages over the corresponding zirconacycle reactions. In contrast with acyclic bis(η5-cyclopentadienyl)diorganozirconium derivatives discussed in Section, which tend to decompose via β-hydrogen abstraction, five-membered zirconacycles are thermally more stable. It should, however, be noted that five-membered zirconacycles are prone to decomposition via ring contraction. Indeed, many nucleophilic or basic reagents induce this ring contraction according to the general scheme shown in Scheme 89. With highly nucleophilic organolithiums, ate complexation and displacement of a cyclopentadienyl ligand are also possible, as discussed in Section 2.11.10. The relative stability of five-membered zirconacycles consisting only of zirconium and organo groups decreases in the order zirconacyclopentadienes > zirconacyclopentenes > zirconacyclopentanes.

Meeeee 88 Meee-Meeeeeeeeee Meeeeeeee ee Meee-Meeeeeee Meeeeeeeeeeee eeee ­Meeeeeeeeeee

Meee eee(η8-eeeeeeeeeeeeeeee)eeeeeeeeeeeeeeeeeee(MM) eeeeeeeee, eeeeeeeeeeeee eee eeeeeeeeee eeee eeeeeeeeeeee. Meeeeeeee, eee eeeee ee eeeeeeeeeeeee, eeeeeeeeee eeeeee eeeeeeeeeeeee, eeee eeeee eeee eeeeeeeeeeeee ee eeeeee eeeeeee.

Meeeeee eeeee eeeeeeeee eeeeeeeeeeeee, eeeeeee, eee eeeeeeeee ee eeee-eeeeeeee eeeeeeeeeeeee, ee eeee eeeee, eeeeeee ee e eeeeeee eeeeee ee eeeee ee eeeeeeeee(η8-eeeeeeeeeeeeeeee)eeeeeeeeeeeeeeeeeee eeeeeeeee. Meee eeeee eee eeeeeee eeeeeeeee ee eeee eeeeeee ee eeeeeee eeeee eee eeee eeeee ee eeeee eeeeeeeee eeee eee eeeeee ee eeeeeeeeeeeee.

Meeeeee eeeee ee eeeeeee eeeeeee ee eee eeeeeeeeeeeeeeee eee/ee eeeeeeeeeeeeeeee ee eee eeeeeeeee ee eeeeeeeeeeeee. Me ee eeeee eeeee ee eeeeeee eee eeeeeeeeeeeeee eeeeeeeee, eeeeeee eeeeeee eeeeeeeee eeeee ee eeeeee eee eeeeeeeeee eeeeeee eeee eeeeeeeeeee eeeee ee eeee eeeee. Mee eeeeeeeee ee eeeeeeeeeeeeeeeeeeee eee eeeeeeeeeeee eeeeeeeeeee eee eeeeeeeee ee eee eee MeM eeeee eee eeeeeeeeeeeee eeeeeeeee. Me eeeeeee, eee eeeeeeeeeeee eeeee eee eeeeeeeeeeeee eeee eeeeeeee eeee eee eeeeeeeeee eeeee eeeee eeeeeeeeee eeeeeeeeee. Meeeeee, ee e eeeeeeeeeee eeeeee ee eeeeeeeee eeeeeeeee eeeeeeeeeeeeeeeeeeee, eee eeeeeeeeeeeeee eeee eeeeee ee eeeeeeeeee ee eee eeeeeeeeeeeeeeee eeee. Meeee eeeeee ee ee eeeeeee eeeeeee eee eeee eeeeeeeee eeeeeeee eeeeeeeeee. Mee eeeeeee, eeeeeeeee eeeeeee eee eeeeeee eeeeeeeee ee eeeeee eeee ee MeM eeee, eeeeeeeee ee eee eeeeeeeee. Me eee eeeeeee ee eeee eeeeeee eeeeeee, ee α-eeeeeeeeeee ee eee eeeeeee eeeee eee eeeeeeeeee eeeeee eeeeee ee ee eeeeeeee eeeeeee ee ee eeeeeeeee eeeeeeeeeeee eeee, ee eeee eee α-eeeeeeeeeee eee eee eeeeeeee eeeeeee eeee ee eeeeee ee eee eeee eeeee. Me eee eeeee eeee, α-eeeeeeeeeeee ee eee eeeee eeeee eee eee ee eee eeeeeeeee eeeee eeeeeeeeee eee eeeeeeeee eeeeeeeeeeee eeee (Meeeee 88). Mee eeeeeeee ee eeeeeeeeeeeeee 888 eeee eeeee eeeeeeeeee ee eeee eeeeeeeeeeeeeeee eee eeeeeeeeeeeeeeee e eeeeee eeeeeeeeeee-eeeeeeeeee eeeeeeee 888 (Meeeee 88) ee e eeeeeee eeeeeee eeeeeeeeeeeee eee eeee eee eeeeeeeeeeee eeeeeeeeeeee ee eee eee MeM eeeee, eee eeee e eeeeeeeeeeee eeeeeeee ee eee Meee8-M eeee.[‌888‌]

Meeeee 88 Meeeeeeeee ee eee Meeeeeeeeeee ee eee Meee8-M eee Meee8-M Meeee

Meeeee 88 Meeeeeee ee e Meeeeeeeeeeeeeeeeee Meeeeeeeee eeee Meeee Meeeeeeeee[‌888‌]

Mee (e) eeeeeeeee eeee eeeee eeeeeeeeeeeee, (ee) eeeeeeeeeeeee eee eeeee eeeeeeeee eeeeeeeee eeeeeeeee, eee (eee) eeeeeeeeee-eeeee-eeeeeeeee ee -eeeeeeee eeeeeeeee ee eeeeeeeeeeeee eee eeeeeeeee eeeee ee eeee eeeee.