Categories: Synthesis of N-Heterocycles > benzo-fused N-Heterocycles >
Synthesis of isoquinolones
Recent Literature
In rhodium-catalyzed C-H activation/annulation reactions for the synthesis of
sixteen 3,4-unsubstituted isoquinolones, vinyl acetate emerges as a convenient
acetylene equivalent. The complementary regiochemical preferences of enol ethers
versus enol esters/enamides is discussed.
N. J. Webb, S. P. Marsden, S. A. Raw, Org. Lett.,
2014,
16, 4716-4721.
A Suzuki cross-coupling between 2-halobenzonitriles and commercially
available vinyl boronates followed by platinum-catalyzed nitrile hydrolysis and
cyclization enable a facile and expeditious two-step synthesis of
3,4-unsubstituted isoquinolin-1(2H)-ones.
S. Jaime- Figueroa, M. J. Bond, J. I. Vergara, J. C. Swartzel, C. M. Crews, J. Org. Chem., 2021, 86,
8479-8488.
N-Chloroamides can be used as a directing synthon for cobalt-catalyzed
room-temperature C-H activation. The reaction with alkynes as coupling partner
provides isoquinolones, a class of synthetically and pharmaceutically important
compounds.
X. Yu, K. Chen, S. Guo, P. Shi, C. Song, J. Zhu, Org. Lett.,
2017, 19, 5348-5351.
A simple and robust procedure for the Rh(III)-catalyzed [4+2] cycloaddition
of feedstock gases enabled through C-H activation provides a diverse set of
3,4-dihydroisoquinolones and 3-methylisoquinolones in very good yields. The
effects of using ethylene and propyne as coupling partners on C-H site
selectivity have been explored with a representative set of substrates.
J. S. Barber, D. Kong, W. Li, I. J. McAlpine, S. K. Nair, S. K Sakata, N.
Sun, R. L. Patman, Synlett, 2021,
32,
202-206.
KOtBu-promoted SNAr reaction of 2-halobenzonitriles with
ketones followed by Cu(OAc)2-catalyzed cyclization gives isoquinolone
derivatives in good yields.
M. S. Mayo, X. Yu, X. Feng, Y. Yamamoto, M. Bao, J. Org. Chem.,
2015,
80, 3998-4002.
The isoquinolone scaffold can be arylated using aryliodonium salts as the
coupling partners at either the C4 or C8 position. The C4-selective arylation
was successfully achieved via an electrophilic palladation pathway, whereas an
Ir(III) catalytic system resulted in C-C bond formation exclusively at the C8
position.
S. Lee, S. Mah, S. Hong, Org. Lett.,
2015,
17, 3864-3867.
The isoquinolone scaffold can be arylated using aryliodonium salts as the
coupling partners at either the C4 or C8 position. The C4-selective arylation
was successfully achieved via an electrophilic palladation pathway, whereas an
Ir(III) catalytic system resulted in C-C bond formation exclusively at the C8
position.
S. Lee, S. Mah, S. Hong, Org. Lett.,
2015,
17, 3864-3867.
A Rh(I)-catalyzed intermolecular cyclization between benzocyclobutenols and
isocyanates provides isoquinolin-1(2H)-ones via a selective cleavage of a
C-C bond. A Rh(I)-catalyzed three-component reaction of benzocyclobutenols,
isonitriles, and sulfonyl azides gives isoquinolin-1(2H)-imines.
Y. He, C. Yuan, Z. Jiang, L. Shuai, Q. Xiao, Org. Lett.,
2019, 21, 185-189.
A sulfilimine is utilized as a directing group for Rh(III)-catalyzed C-H
activation/annulation with intermolecular and intramolecular alkyne compounds.
The sulfilimine serves both as a transformable directing group and an internal
oxidant via N-S bond cleavage. A Rh(III)-catalyzed ortho-alkynylation
with alkyne bromides preserves the sulfilimine.
J. Liu, X. Jia, L. Huang, Org. Lett.,
2022, 24, 6772-6776.
A Rh-catalyzed redox-neutral annulation of primary benzamides with diazo
compounds provides isoquinolinones. This efficient and economic procedure
exhibited good functional group tolerability, scalability, and regioselectivity,
obviating the need for oxidants, and only environmentally benign N2
and H2O were released.
Y. Wu, P. Sun, K. Zhang, T. Yang, H. Yao, A. Lin, J. Org. Chem.,
2016,
81, 2166-2173.
A chemoselective ruthenium(II) catalysis enabled mild reaction conditions for
positional selective annulations of bromoalkynes to provide isoquinolones with
organic substituents distal to nitrogen - complementary to previous
protocols.
H. Huang, S. Nakanowatari, L. Ackermann, Org. Lett.,
2017, 19, 4620-4623.
A novel Pd-catalyzed cascade dehydrogenative cross-coupling/annulation reaction
of N-alkoxybenzamides with β-keto esters enables the synthesis of
isoquinolinone derivatives. A plausible mechanism involves α-C(sp2)-H
activation and a Pd(II)/Pd(IV) catalytic cycle.
G.-D. Xu, Z.-Z. Huang, Org. Lett.,
2017, 19, 6265-6267.