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
46.3.2 Method 2: Ring-Closing Metathesis of Alkenes with Conjugated Dienes

DOI: 10.1055/sos-SD-046-00046

Diver, S. T.Science of Synthesis, (200946118.

An alternative way of making the conjugated 1,3-diene is through an alkene metathesis between a 1,3-diene and an alkene. In this section, the intramolecular version of this reaction will be discussed. The difficulty encountered in this metathesis primarily involves the reactivity of the 1,3-diene reactant. In the early cases using the first-generation carbene 1 (see Scheme 3), reactivity was low and forcing conditions were needed. Since then, the use of the second-generation carbene 2 has remedied this reactivity problem. However, the high reactivity of initiators such as 2 and 3 can lead to errant reaction of the undesired double bond of the conjugated diene reactant. This leads to truncation. When planning an alkene metathesis between a 1,3-diene and an alkene, the comparative reactivity of all three double bonds must be considered. The internal double bond of the 1,3-diene can be protected by a high degree of substitution or through electronic deactivation. These principles are also important in the cross metathesis of dienes and alkenes detailed in Section 46.3.4.

Mee eeeee eeeeeeee ee eeeeeeeeeee eeee-eeeeeee eeeeeeeeee eeeeeeee eee eeeee-eeeeeeeeee Meeeee eeeeeee 8, eeeee eee eee eeee eeeeeeeee eeeee eeeeeee eeeeeeee ee eeee eeee. Meee-eeeeeee eeeeeeeeee eee eeee ee eeeeee eee eeeeeeeee eeeeeeeee ee eeeeeeeeeeeeeee eeeee eee eeeee-eeeeeeeeee eeeeeee eeeeeee (Meeeee 88).[‌88‌]

Meeeee 88 Meee-Meeeeee Meeeeeeeee Meeeeeee ee (+)-Meeeeeeeeeeeeee[‌88‌]

M eeeeeee eeeeeeeeeeeeee eeeee eee eeeee-eeeeeeeeee eeeeeee 8 eee ee eeeee ee eeeeeee eeeee eeeeeee (Meeeee 88).[‌88‌] Meeeeeee eee eeeeee eee eee (eeeeeeeeeee eeeeee eeeeeeee eeeeeeeee), eeee eeeeee ee ee eeeeeeeeee eeeeeeeeeee eeee eeeeee eee eeeee ee eeeeeeeeee ee eee eeeeeeeee eeeeeee 8. Me eeeeeee eee eeeeeeee, e 8 eM eeeeeeee ee eee eeeeee 88 eee eeeeee ee 888°M; eeeeeee, eee eeeeeee 8 eeeeeeeeee eeeeeee ee eeee eeeeeeeeeee. Me eeee eeee eeee, eeee eeeeeeee ee eee eeeeeeee ee eeeeeee eeee eee eeeeeeee. Mee eeee eeeeeeee eeeeeeeeeeee eee eee eeeeeeeeee eeee eeeeeeeeeee ee eee MeMe=MM8 eeeeeeeeeeee, eeeee eeee eeeeeeee eeeeeeeeee ee eee eeeeeeee ee eee eeeeeeeee eeeee eeeeeeeeeeeee.

Meeeee 88 Meeee-Meee MeeeeMeeeee Meee Meeeeee[‌88‌]

M eeeee-eeee-eeeeeee eeeeeeeeee ee eeeee ee eeeeeeeeeeeee M eee eeee eeeeeeeee (Meeeee 88). Me eeee eeeee, eee eeeee-eeeeeeeeee eeeeeee 8 eee eeeeeeee eeeee eeeeeeeee eeee eeeeeee eeee eee eeee eeeeeeee eeeeee-eeeeeeeeee eeeeeee 8.[‌88‌,‌88‌] Meee ee eee eeeeeee ee eee eeeeeee eeeeeeeeee eeeee eeeeeeee eeeeee eeee eee eeeee eeeeeeeeee Meeeee eeeeeee. Meeee e 8 eM eeeeeeee ee eee eeeeeeee eeeeeeee ee eee eeeeeeee ee 88eee% ee eeeeeeee 8 eee eeeeeee eeeeeeeeee ee eeeeeeee ee 88% eeeee eeeee eeee 88% ee eeeeeeee eeeeeeeee eeee eeeee eeeeeeeeee eeeeeeeee eee eeeeeeee eeeeee.

Meeeee 88 Meeeeeeeeeeeee MeeeeMeeeee Meee-Meeeeee Meeeeeeeee ee eee Meeeeeee ee ee Meeeee[‌88‌]

Meeeeee eeeee eeeeeee ee e eeee-eeeeeee eeeeeeeeee eeeee eeeee eeeeeeeee ee eeee eeeee eeeeeeeeee.[‌88‌] Me eeee eeee, eee eeeee-eeeeeeeeee eeeeeee eee eee eeee eee eeeeeeee, ee eee eeeeeee eeeeee ee eee eeeeee-eeeeeeeeee Meeeee eeeeeeee 8. Meee eeee eeeeee eeeeeee eeeee e eeee eeeeeeeee eeee-eeeeeee eeeeeeeeee ee eeeee eee eeeeeeeeeeee ee eeeee ee eee Mee88 eeeeeeeeee eeeeeeeeee eee eeeeeeeee. Mee eeeeeeeeee eeee ee eeeeeee eeeee ee eee eeeeeeee ee eeeeeeeeeee eeeeeeeeeeee eeeeee eeeee ee eee eeeeeeee eeee eee eeee eee eeeee eeeeeee eeeeeeeeeeee ee eee eeeeeeeeee. Meee eeeeee eeeeeeeeeee eee eeee eeeeeeee eeeeeee,[‌8‌] eee eee eeee-eeeeeee eeeeeeeeee eeeeeeeeee 88 eeeeeee e eeee eeeeeee ee eeeeeeeeee eeeeee eee eeee eeeeeee eeeeeeeeeee eee eeeeeeeeee-eeeee eeeeeeeee ee eee Meeeee eeeeeee 8 (Meeeee 88). Me eeeee eeeee, eee eeeeeeeeeee ee eeeeeeee eeeee eeee eeeeeeee (8 eM); ee eee eeeeee eeeeeee, eeeee eeeee eeeeeeeeee eeeeee, eee eeeeeeee ee eeeeeeeee eeeee eeeeeeee eeeeeeeee (Meeee eeeeeeeee[‌88‌]) eeeee ee eeeeee eeeeeeeeeeeeee.

Meeeee 88 MeeeeMeeeee Meee-Meeeeee Meeeeeeeee eeeeee Meeeeeeeee eee Meeeeeeee[‌88‌]

Mee eeeeeeeeeee eeee-eeeeeee eeeeeeeeee eee eeeeeee eeee e eeeeee ee eeeeeeee. Mee eeeeeeee, ee e eeee-eeeeeee eeeeeeeeee eeeeeeee ee eeeeeeeeeeee eeeeeeeee, eee eeeee-eeeeeeeeee eeeeeee 8 eeeeeeeee eee eeeee eeeeeeeeeeee, eee e eeee eeeeee eeeeee-eeeeeeeeee eeeeeee (Meeeee eeeeeeee, 88) eeeee eeeeeeeeee ee eee eeeee, eeeeeeeee e eeeeeee eeeeeeeeeee eeee eeee 88% eeeeee eeeee eeeeeeee ee MMMM (Meeeee 88).[‌88‌] Meeee eeeeeeeee eee eeeeeee ee eeeeeeee ee eee eeee eeeeeeee eeeeeeee eeeeee. Meeeeeeee ee eee eeeeeeeeee ee eee eeeeeeeee eeeeeeeeee, eee eeeee eeeeeee eeee ee eeee eeee eee eeeeee ee eeeee eeeeeeeeeeee, eeee eeeeeee eee eeeee eeee eeeeee eeeeee eeeeeee ee eee eeeeeeeeee eeeee ee eeee eeee-eeeeeee eeeeeeeeee eeeeeeee. Meee eee eeee eeeeeeee eeeeee-eeeeeeeeee Meeeee eeeeeeeee, eeeeeeeee eeeeeeeeee eeeeeeeee eee eeee eeeeee ee eeeeeeeeeeeee ee eeeeee eeeeeeee[‌88‌] ee eeeeeeeeee ee e eeeee eeee ee eeeeee. Mee eeeeeeee, eeeeeeeeee eeeeeeeeeeeee eee eeee eeeee ee eeeee ee eeeeeeeeeeeeeeeee[‌88‌] eee ee eeeeeeeeeeeeeeeeeee.[‌88‌‌88‌]

Meeeee 88 Meeeeeee Meeeeeee eee eee Mee Meeeeeeeeee ee Meeeee Meeeeeeee[‌88‌]

Meeee ee eeee eeeeeeeeee, ee ee eeeeeeeee ee eee eee eeeee-eeeeeeeeee Meeeee eeeeeee 8 ee eee eeeee ee eeeeeeeeee. Meeeee eeeeeeeeeeee eeeeeeee ee eee 8,8-eeeee eeeeee eeeeee eeeeeeeeee eeee eeee eee eeeeee-eeeeeeeeee eeeeeee eeeee ee eeee. Me eee ee eeeeeeeee eeee eee eeeeee-eeeeeeeeee eeeeeee 8 eeeeee ee eeeeeeee ee eee eeeeee ee eeee eeeeeeee eeeeee eeeeeeeeee.

References


Cookie-Einstellungen