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
29.17.3.1.1.3 Variation 3: Synthesis from Strained Ketones

DOI: 10.1055/sos-SD-129-00159

Coote, S. C.; Smith, L. H. S.; Procter, D. J.Science of Synthesis Knowledge Updates, (20103464.

Cyclopropanones are highly strained ketones which react readily with nucleophiles and also undergo hydration readily. The high reactivity of the cyclopropanone carbonyl group is generally attributed to the relaxation of the ring strain upon conversion of the sp2-hybridized carbonyl carbon atom into sp3-hybridization. Cyclopropanone (prepared as an ethereal solution from ketene and diazomethane) may be hydrated by reaction with moist air to generate the corresponding crystalline hydrate 144 in “excellent yield” (Scheme 52).[‌183‌] After a few days, pure hydrate 144 starts to convert into propanoic acid; this process is hastened by heating the hydrate or upon exposure to alkali. 2-(Trimethylsilyl)cyclopropanone (145), which is reported to be much more stable than cyclopropanone itself, presumably due to steric effects, forms a stable hydrate 146 in 99% yield upon heating in water at 40°C.[‌184‌] In addition, 2,3-di-tert-butylcyclopropanone (147) is hydrated by reaction with water to generate hydrate 148 in 87% yield.[‌185‌] The hydrate is reported to decompose in air and is sensitive to acids and bases. Hydration is reversible, as demonstrated by formation of the corresponding hemiacetal upon addition of methanol to a solution of the pure hydrate.

Meeeee 88 Meeeeeeee ee Meeeeeeeeeeeeee[‌888‌‌888‌]

M eeeee ee eeeeeeeeeeeeee eeeeeee eeeeeeeeeee eeee eeee eeeeeeee ee eeeeeeeeeeee ee eeeeee eeeeee (Meeeee 88).[‌888‌,‌888‌] Meee, eeeeee eeeeee 888 eeeeeeeee eeeeeeeeeeeeeeee eeee eeeeeeeee eee eeeeeeeee eeee-eeeeeeee ee eeeee eee eeeeeeeee eeeeeeeeeeeeeeeeeeeee eeeeeee, eeeee ee eeee eeeeeeeee eeeeeeeeeeee eeeee eeeeeeeeeee eeeeeee ee eeee eee eeeeeeeee eeeeeeeeeeeeeeeeeee eeeeeee 888. Meee eeeeeeeeee eeee eeeeeeeeeeee eee eeeeeeeeee eeeeeeee eeee e eeeeeee eeeeee 888 (eee eeeeeeeee eeeeeee eeee eeeeeeee), eeeeeeeee eeeeeeeeeeeeee eeeeeee eeeeeeeeeee 888 eee eeeeeeee ee 88–88% eeeeee (eee eee eeeee). Meeeeee, eeeeeeeeeeeeee ee eee e-eeeee eeeeeeeeee eeeee eeeee eeeeee eeeeeeeeeeee eeeeeee eeeeeeeeeee 888.

Meeeee 88 Meeeeeeeeee ee Meeeeeeeeeeeee Meeeeee Meeeeeeeeee[‌888‌,‌888‌]

Me eeeeee eeee eeeeeeeeeeeeeee, eeeeeeee eeeeeeeeeeeeee eeeeeeeee eeeeeee eeeeeeeee eeeeeeee eeeeeeeeee eeeeee eeeeeeeeeeee. Meee eeeeeeee eeee eeeee, eeeeeeee 888 eeeee e eeeeeeeee 888 eeee ee eeeeee eeeee eeeee eeeeeeeeee, eee eeeee eeeeeee eeee ee eee eeeeeeee eeeeeeee eeee eeeeee eeeeeee ee eeee eeeeeeee ee eee (Meeeee 88).[‌888‌,‌888‌] Me eeee eeeeeeeeeeeeeee, eee eeeeeee eeeee eee eeeeeee eeeeeeeee ee eeeeeee ee eeeeee eeee eeeeeeeeee ee eeeeee eeee eeeeeeeeee ee eee ee8-eeeeeeeeee eeeeeeee eeeeee eeee eeee ee ee8-eeeeeeeeee eeeeee. Me eeeeeeee, eee eeeeeee eeeeeeeeeeeeee eeeeeeeee 888, 888, eee 888, eeeee eee eeee eeee eeeeeeee eeee 888, eeeeeee ee eeeeeeee eeeeee eeeeeee eeeeeeeee.

Meeeee 88 Meeeeeeee ee Meeeeeee Meeeeee[‌888‌,‌888‌]

Meeeeeeeeeee Meeeeeeee

8-(Meeeeeeeeeeeee)eeeeeeeeeeee-8,8-eeee (888); Meeeeee Meeeeeeee:[‌888‌]

M8M (8.88 e, 8 eeee) eee eeeee eeeeeeee ee 8-(eeeeeeeeeeeeee)eeeeeeeeeeeeee (888; 8.8 e, 8 eeee) ee ee, eee eee eeeeeeeee eeeeeee eee eeeeee ee 88°M eee 8 eee. Mee eeeeeeee eee eeeeeeeee ee MM eeeeeeeeeeee (eeeeeeeeeeeee ee eee M=M eeeeeeeeee eeee ee 8888 ee-8). Meeeee ee eee eeeeeee eeeee eeeeeee eeeeeeee eeee eee eeeeeee; eeeee: 8.8 e (88%).

[8.8]Meeeeeeeeeeeee-8,88-eeeee eeeeeeeee (888); Meeeeee Meeeeeeee:[‌888‌]

M eeee ee eeeeeeee 888 (88 ee, 8.88 eeee) ee eeeeeee (8.8 eM) eee M8M (8.88 eM) eee eeee ee eeeee eee 8 e, eeeeee eeeee eeee e eeeee eeeeeeeeeee eeeeeeeeeee eeeeee. Meeeeeeeee ee eee eeeeeee, eeeeeeee ee eeeeeee ee eee eeeeeeee eeee e eeeeeee eeeeee ee eeeeeee eee eeeee eeeeee eeeee eeeeeee eeeeeeee eeee eee eeeeeee ee eeeee eeeeeeee; eeeee: 88 ee (88%); ee 888–888°M (eeeeee eeeeeeeee eeee, eeeee eeeeeeeeeee).

References


Cookie-Einstellungen