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
26.1.2.2.3 Variation 3: By Ozonolysis

DOI: 10.1055/sos-SD-026-00062

Balaban, T. S.Science of Synthesis, (200526135.

Ozonolysis has been applied as a tool to determine the position of C=C bonds in unsaturated compounds. Ozone adds to C=C bonds to form very reactive ozonides which in some cases can be isolated. The ozonides are subsequently cleaved by hydrolysis under either reductive or oxidative conditions. For the synthesis of ketones the C=C bond must be at least trisubstituted, of which terminal alkenes are the most reactive, or tetrasubstituted. Mechanistically the reaction has been intensively studied by Criegee and co-workers and has been reviewed.[‌66‌,‌67‌] The proposed mechanism is shown in Scheme 13. The initial addition product has been isolated as a crystalline material from the reaction of ozone with (E)-2,2,5,5-tetramethylhex-3-ene,[‌68‌] and could be reduced to the racemic diol proving that one CC bond is still intact after the ozone addition which must occur in a cis fashion. This highly unstable adduct cleaves to a carbonyl oxide, which can be formulated as a zwitterionic species, and to a carbonyl compound. These can recombine in a different way to form the ozonide. Alternatively, the zwitterion, which can also be formulated as a 1,3-diradical, can dimerize to the bisperoxide or oligomerize.

Meeeee 88 Meeeeeee Meeeeeeee eee eee Meeeeeeeee ee Meeeeee

Meee eeeeeeeee eeeeeeee eee eeee eeeeeeeeeeee eeeeeeeeeeee, eeee ee eeeee eeeeeee eeeeeeeee ee eeeee-eeeeeeee eeeeeeeee ee 88M eeeeeeee eeeeeeeeeee. Mee eeeeee eeeee eeee ee 88M-eeeeeee eeeeeeee ee eeeee ee eee eeeeeeeeee eeeeeee, eee eeeee eeee ee eeeeeeeeeeee ee eee eeeeeeee eeeeee eeee eee eee ee eee eeeeee eeeeee. M eeeeeeee eeeeeeee eeeeeeeee eee eeee eeeeeeee eeee eeeeeeee.[‌88‌]

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

Meeeee 88 Meeeeeeee ee Meeeeee ee Meeeeeeeee[‌88‌‌88‌]

Me eee eeee eeeee eeee eeee- eee eeeeeeeeeeeee eeeeeeeeeeeee eeee eeeeeeeeeeeee eeeeee eeeeeeee, eeeee eee eee eeeeeee ee eeeeeeeeeeeeeeeeee, eeee ee eeeeeee eeeeeeeeeeeeeee.[‌88‌] Me eeeeeeee ee eeeee, eeee eeeeeeeeee eeeeeeee eeeeeeeeeeeeeeeeeeeee eee eeeeeeeeeeeeeeeeeee eeeeee eee eeeeeeeeeeeee eeeeeee eeeeeeeeeeeeee. Meeeeeeeee, eee eeee ee eeeeeeeeee eeeeee eeeeeeeeee eee eeeeeeeee ee eeeee eeeee ee eee ee eee eeeeeee eeeeee eeeeee ee eee eeeeeee eeeeeeeee ee eee eeeeeeeeeeee.

Meeeeee ee eee eeeeeeeee eeeeeee ee eeeeeeeeeee eeeee eeeeeeeeeee, eee eeeee ee eee eeeeeeeee ee eeeee eeee (M)-eee-8-eee, (M)-eee-8-eee, eee 8-eeeeeeeee-8-eee eeee eeee eeeeeeeee eeeeeeee eeeee eeeeeee eeeeeeeeee eeeeeeeee eee eeeeeeeeee ee eeeeeeee eeeeeeee.[‌88‌]

Meeeeeeeeeee Meeeeeeee

Meeee-8-eee (88); Meeeeee Meeeeeeee:[‌88‌]

MMMMMMM: Meeee eeeeeeeee eeeeee eeeeeeeee eee eee eeeee eee ee eeeeee eeeeeeeee ee eee eeeeee ee eeeee. Meeeeeeee eee eeeeeeeeeeeee eeeeee ee eeee ee e eeee-eeeeeeeeee eeee eee eeeeee e eeeeee eeeeee eeeeee.

M eeee ee 8-eeeeeeeee-8-eee (88e, 8.8eee) ee MM8Me8 (888eM) eee eeeeeee ee eeeee ee 88°M eee 88e eeee M8 ee eeeeeeee ee M8 eeeeee (ee. 88M·e8) eeeeeeeeee 8% M8. Mee eeeeeee eee eeeee eeeeee 88eee eeeee eeeeeeee ee e eeeeeeeeee ee Me eeee (88.8e) ee 88% ee MeMM (888eM). Mee eeeeeeeeee eeeeeeee eeeeeeeeeeee eeeeeeeeee MM8Me8 ee eeeeeeeeeeee. Meeee eeeeeeee eee eeeeeeee, eee eeeeeeeee eeeeeee eee eeeeeeee eee 8e, eeee eeeeee, eee eeeeeeeee eeee Me8M (888eM). Mee Me8M eeeee eee eeeeee eeeeeee eeeee eeee e eeee ee MM eeeee eee eee eeeeeeeee eeee eeeeeee (eeee eeee eeeeee eeeeeeee eeeeeeeee eeeeee, eeeee eee eeee ee eeeeeee eeeeeeeeee eeee eeeeeeeeeeee). Mee eeeeeee eeeee eee eeeeee eeeeeeeeeeee eeee eee MeMM eeee, eee MMe eeee, eee eeeeeee eeee eeeee. Mee eeeeeee eee eeeee eee eeeeeeee ee eeeeeeeeeeee (ee 888888.8°M); eeeee: 88%.

References


Cookie-Einstellungen