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.
Functionalized α-tertiary and -quaternary 2-arylcycloalkanones are rapidly
accessed by scandium(III) triflate-catalyzed diazoalkane-carbonyl homologations.
Pairing readily available bis- and tris(oxazoline) based ligands with scandium
triflate allows access to arylated medium ring carbocycles with high
enantioselectivities and excellent yield.
V. L. Rendina, H. Z. Kaplan, J. S. Kingsbury, Synthesis, 2012,
686-693.
V. L. Rendina, H. Z. Kaplan, J. S. Kingsbury, Synthesis, 2012,
686-693.
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.
