Categories: C=C Bond Formation >
Synthesis of substituted active methylenes
Name Reactions
Recent Literature
Triphenylphosphine is an efficient catalyst for a mild, solvent-free
Knoevenagel condensation of aldehydes with ethyl cyanoacetate or
malononitrile to afford olefins in excellent yields with (E)-geometry.
This method, which is even improved by microwave irradiation, is applicable
for a wide range of aldehydes.
J. S. Yadav, B. S. S. Reddy, A. K. Basak, B. Visali, A. V. Narsaiah, K.
Nagaiah, Eur. J. Org. Chem., 2004, 546-551.
Iridium-catalyzed hydrosilylation of tertiary amides followed by
acid-mediated condensation with active methylene compounds provides
multifunctionalized non-N-containing products. This scalable method is
broad in scope and shows remarkable chemoselectivity for the amide group in the
presence of functionalities such as ester, cyano, nitro, silyl dienol ether, and
ketone.
D.-P. Wu, W. Ou, P.-Q. Huang, Org. Lett.,
2022, 24, 5366-5371.
1,3-dicarbonyl compounds and methyl ketones or terminal aryl alkenes as simple
and readily available starting materials can be efficiently converted to
unsymmetrical 1,4-enediones under mild reaction conditions using a focusing
domino strategy. The reaction allows an operationally simple, straightforward
synthesis of various unsymmetrical 1,4-enediones.
M. Gao, Y. Yang, Y.-D. Wu, C. Deng, L.-P. Cao, X.-G. Meng, A.-X. Wu, Org. Lett., 2010,
12, 1856-1859.
A mild, palladium-catalyzed intramolecular oxidative alkylation of various ζ-alkenyl β-diketones
and ζ-alkenyl β-keto
esters in the presence of CuCl2 at room temperature formed the
corresponding 2-cyclohexenones in high yield.
T. Pei, X. Wang, R. A. Widenhoefer, J. Am. Chem. Soc., 2003, 125, 648-649.
An efficient and regioselective Yb(OTf)3-promoted
palladium-catalyzed oxidative cyclization of γ-heteroalkenyl β-keto amides
has been developed. Under simple aerobic condition, various six-, seven-,
and eight-membered-ring N- and O-heterocycles were obtained in excellent yield.
K.-T. Yip, J.-H. Li, O.-Y. Lee, D. Yang, Org. Lett.,
2005, 7, 5717-5719.
