Categories: C-C Bond Formation > Cyclic compounds >
Ring-Expansion
Recent Literature
The reaction of β-keto esters with CF3CO2ZnCH2I
provided the corresponding chain-extended products in moderate to good
yields. α-Substituted acyclic β-keto esters reacted less efficiently than
cyclic β-keto esters or simple β-keto esters.
S. Xue, Y.-K. Liu, L.-Z. Li, Q.-X. Guo, J. Org. Chem., 2005,
70, 8245-8247.
The homologation of arylcyclobutanones with trimethylsilyldiazomethane gives
enolsilanes in the presence of Sc(OTf)3 as catalyst with a high
preference for methylene migration, whereas Sc(hfac)3 leads to
β-ketosilanes. Each adduct affords the cyclopentanone upon hydrolysis.
J. A. Dabrowski, D. C. Moebius, A. J. Wommack, A. F. Kornahrens, J. S. Kingsbury, Org. Lett., 2010,
12, 3598-3601.
A stereospecific gold(I)-catalyzed rearrangement of 1-alkynyl cyclobutanols
and cyclopropanols provides alkylidene cycloalkanones. The reaction
tolerates terminal alkynes as well as alkyl, aryl, and halo-substitution at
the acetylenic position and substituents on the ring.
J. P. Markham, S. T. Staben, F. D. Toste, J. Am. Chem. Soc.,
2005,
127, 9708-9709.
Oxidative ring expansion of methylenecyclopropanes with CAN under oxygen
atmosphere was investigated. A facile conversion affording
2,2-diarylcyclobutanones occurred in good yields.
V. Nair, T. D. Suja, K. Mohanan,
Synthesis, 2006, 2531-2534.
[ReBr(CO)3(thf)]2 catalyzes the reaction of a
1,3-dicarbonyl cyclic compound with an acetylene to give a medium-sized cyclic
compound in excellent yield. By using isocyanide as an additive, the insertion
of acetylenes into a carbon-carbon single bond occurs under mild conditions.
Y. Kuninobu, A. Kawata, K. Takai, J. Am. Chem. Soc., 2006,
128, 11368-11369.
