Categories: C-C Bond Formation > Carbocyclic compounds > Cycloalkenes
Synthesis of cyclobutenes
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Recent Literature
The facile preparation of organoboronates and their remarkable stability and
functional group tolerance enable straightforward syntheses of four- and
five-membered carbo- and heterocycles via in situ transmetalation of sensitive
organometallics with boron alkoxides.
A. N. Baumann, M. Eisold, A. Music, D. Didier, Synthesis, 2018, 50,
3149-3160.
Gold catalysis enables an efficient intermolecular [2+2] cycloaddition between
two different types of chloroalkynes and unactivated alkenes. Monosubstituted
unactivated alkenes can be converted with excellent regioselectivities. With
1,2-disubstituted unactivated alkenes, the reaction is largely stereospecific.
Y.-B. Bai, Z. Luo, Y. Wang, J.-M. Gao, L. Zhang, J. Am. Chem. Soc.,
2018,
140, 5860-5865.
The use of sterically hindered cationic Au(I) complexes as catalysts enables a
regioselective, intermolecular reaction of terminal alkynes with alkenes to give
cyclobutenes.
V. López-Carrillo, A. M. Echavarren, J. Am. Chem. Soc., 2010,
132, 9292-9294.
Palladium-catalyzed cross-coupling reactions of cyclobutanone-derived N-sulfonylhydrazones
with aryl or benzyl halides provide structurally diversified products including
cyclobutenes, methylenecyclobutanes, and conjugated dienes in very good
yields. The reaction also offers a promising route for the synthesis
of enantioenriched four-membered-ring molecules.
X. Ning, Y. Chen, F. Hu, Y. Xia, Org. Lett., 2021, 23,
8348-8352.
A catalytic intermolecular [2 + 2] cycloaddition of terminal alkynes with
electron-deficient alkenes proceeds in the presence of 8-quinolinolato rhodium/phosphine
catalyst system to give cyclobutenes from various substrates in high yields and
with complete regioselectivity.
K. Sakai, T. Kochi, F. Kakiuchi, Org. Lett., 2013,
15, 1024-1027.
An In(tfacac)3-TMSBr catalyzed selective [2 + 2]-cycloaddition
enables an efficient synthesis of cyclobutenes from aryl alkynes and acrylates
with high chemo- and stereoselectivity. Densely functionalized decalin skeletons
can be produced through a dearomatizing cascade reaction. The obtained
cyclobutenes could be easily converted into cyclobutanes as well as
synthetically useful 1,4- and 1,5-diketones with high chemo- and
stereoselectivity.
L. Shen, K. Zhao, K. Doitomi, R. Ganguly, Y.-X. Li, Z.-L. Shen, H. Hirao, T.-P.
Loh, J. Am. Chem. Soc., 2017,
139, 13570-13578.
Chiral bisoxazoline copper(I) complexes catalyze an enantioselective [3 +
1]-cycloaddition of two structurally different diazo compounds to provide
cyclobutenes containing a quaternary stereocenter.
Y. Xu, Z. Wang, J. Sun, Org. Lett., 2021, 23, 7613-7617.
A nickel-catalyzed intermolecular [2 + 2] cycloaddition of conjugated enynes
with electron-deficient alkenes as well as electronically neutral norbornene
leads to cyclobutenes. The use of conjugated enynes circumvented possible side
rections, such as oligomerizations and cyclotrimerizations. η3-Butadienyl
coordination is the key for the selective formation of cyclobutenes.
A. Nishimura, M. Ohashi, S. Ogoshi, J. Am. Chem. Soc., 2012,
134, 15692-15695.
Cobalt-catalyzed transformations of cyclic alkenes such as cyclopentene and
cycloheptene with internal alkynes led to a chemoselective Alder-ene or a [2 +
2] cycloaddition reaction depending on the electronic nature of the alkyne and
the bite angle of a bidentate phosphine ligand used.
G. Hilt, A. Paul, J. Treutwein, Org. Lett., 2010,
12, 1536-1539.
