A. J. Zheng et al./Chemical Papers 67 (10) 1271–1276 (2013)
1275
urated ketones and esters clearly demonstrates that
the reactivity of unsaturated esters is lower than that
of unsaturated ketones (Pelšs et al., 2009). A 95 %
yield of saturated ester was obtained from ethyl cy-
clohexylideneacetate, a β,β-disubstituted unsaturated
ester, using the CuF(PPh3)3 ·2MeOH–DPEphos cat-
alyst (entry 6). For diethyl 2-benzylidenemalonate, an
α-substituted unsaturated ester, 2 mol % of the cata-
lyst was required to obtain the reduced ester in a 89 %
yield within a reasonable reaction time (entry 7). The
catalytic system is also applicable for the reduction of
α,β-unsaturated mononitrile (entry 8).
Ito, H., Ishizuka, T., Arimoto, K., Miura, K., & Hosomi,
A. (1997). Generation of reducing reagent from cop-
per(I) salt and hydrosilane. New practical method for con-
jugate reduction. Tetrahedron Letters, 38, 8887–8890. DOI:
10.1016/s0040-4039(97)10326-4.
Jung, C. K., & Krische, M. J. (2006). Asymmetric induction
in hydrogen-mediated reductive aldol additions to α-amino
aldehydes catalyzed by rhodium: Selective formation of syn-
stereotriads directed by intramolecular hydrogen-bonding.
Journal of the American Chemical Society, 128, 17051–
17056. DOI: 10.1021/ja066198q.
Jurkauskas, V., Sadighi, J. P., & Buchwald, S. L. (2003). Conju-
gate reduction of α,β-unsaturated carbonyl compounds cat-
alyzed by a copper carbene complex. Organic Letters, 5,
2417–2420. DOI: 10.1021/ol034560p.
a
Kim, D., Park, B. M., & Yun, J. S. (2005). Highly efficient
conjugate reduction of α,β-unsaturated nitriles catalyzed
by copper/xanthene-type bisphosphine complexes. Chemical
Communications, 2005, 1755–1757. DOI: 10.1039/b418586b.
Lee, D. W., & Yun, J. S. (2004). Copper-catalyzed asymmet-
ric hydrosilylation of ketones using air and moisture stable
precatalyst Cu(OAc)2 · H2O. Tetrahedron Letters, 45, 5415–
5417. DOI: 10.1016/j.tetlet.2004.05.048.
Lee, C. T., & Lipshutz, B. H. (2008). Nonracemic diaryl-
methanols from CuH-catalyzed hydrosilylation of diaryl ke-
tones. Organic Letters, 10, 4187–4190. DOI: 10.1021/ol8015
90j.
Conclusions
In summary, copper hydride derived from
CuF(PPh3)3 · 2MeOH–DPEphos–PMHS can catalyze
the reduction of electron-deficient olefins, e.g. α,β-
unsaturated ketones, esters, and nitriles, providing
high product yields. The catalyst system might be ap-
plied for the reduction of other polar electron-deficient
—
—
C
C bonds which conjugate to nitro, sulfonate and
phosphite electron-withdrawing groups.
Acknowledgements. Financial support from the National
Natural Science Foundation of China (No. 20972020) is grate-
fully acknowledged.
Li, Z. N., Liu, G. L., & Chiu, P. (2008). Application of H–Cu–P
complexes in organic synthesis. Progress in Chemistry, 20,
1909–1022.
Li, N., Ou, J., Miesch, M., & Chiu, P. (2011). Conjugate re-
duction and reductive aldol cyclization of α,β-unsaturated
thioesters catalyzed by (BDP)CuH. Organic & Biomolecu-
lar Chemistry, 9, 6143–6147. DOI: 10.1039/c1ob05352c.
Lipshutz, B. H., Keith, J., Papa, P., & Vivian, R. (1998). A
convenient, efficient method for conjugate reductions using
catalytic quantities of Cu(I). Tetrahedron Letters, 39, 4627–
4630. DOI: 10.1016/s0040-4039(98)00855-7.
Lipshutz, B. H., Chrismanm, W., Noson, K., Papa, P., Sclafani,
J. A., Vivian, R. W., & Keith, J. M. (2000). Copper hydride-
catalyzed tandem 1,4-reduction/alkylation reactions. Tetra-
hedron, 56, 2779–2788. DOI: 10.1016/s0040-4020(00)00132-0.
Magnus, P., Waring, M. J., & Scott, D. A. (2000). Conjugate re-
duction of α,β-unsaturated ketones using an MnIII catalyst,
phenylsilane, and isopropyl alcohol. Tetrahedron Letters, 41,
9731–9733. DOI: 10.1016/s0040-4039(00)01728-7.
References
Baker, B. A., Boškovi´c, Ž. V., & Lipshutz, B. H. (2008).
(BDP)CuH: A “hot” Stryker’s reagent for use in achiral
conjugate reductions. Organic Letters, 10, 289–292. DOI:
10.1021/ol702689v.
Blackwell, J. M., Morrison, D. J., & Piers, W. E. (2002).
B(C6F5)3 catalyzed hydrosilation of enones and silyl enol
ethers. Tetrahedron, 58, 8247–8254. DOI: 10.1016/s0040-
4020(02)00974-2.
Brestensky, D. M., & Stryker, J. M. (1989). Regioselective con-
jugate reduction and reductive silylation of α,β-unsaturated
aldehydes using [(PH3P)CuH]6. Tetrahedron Letters, 30,
5677–5680. DOI: 10.1016/s0040-4039(00)76168-5.
Chen, J. X., Daeuble, J. F., & Stryker, J. M. (2000). Phos-
phine effects in the copper(I) hydride-catalyzed hydrogena-
tion of ketones and regioselective 1,2-reduction of α,β-
unsaturated ketones and aldehydes. Hydrogenation of decalin
and steroidal ketones and enones. Tetrahedron, 56, 2789–
2798. DOI: 10.1016/s0040-4020(00)00133-2.
Chiu, P., Chen, B., & Cheng, K. F. (1998). A conjugate
reduction-intramolecular aldol strategy toward the synthesis
of pseudolaric acid A. Tetrahedron Letters, 39, 9229–9232.
DOI: 10.1016/s0040-4039(98)02130-3.
Chiu, P., Li, Z. N., & Fung, K. C. M. (2003). An expedient
preparation of Stryker’s reagent. Tetrahedron Letters, 44,
455–457. DOI: 10.1016/s0040-4039(02)02609-6.
Hirasawa, S., Tajima, Y., Kameda, Y., & Nagano, H. (2007).
Conjugate reduction of α,β-unsaturated esters and amides
with tributyltin hydride in the presence of magnesium bro-
mide diethyl etherate. Tetrahedron, 63, 10930–10938. DOI:
10.1016/j.tet.2007.08.059.
Hughes, G., Kimura, M., & Buchwald, S. L. (2003). Catalytic
enantioselective conjugate reduction of lactones and lactams.
Journal of the American Chemcial Society, 125, 11253–
11258. DOI: 10.1021/ja0351692.
Mahoney, W. S., Brestensky, D. M., & Stryker, J. M. (1988).
Selective hydride-mediated conjugate reduction of α,β-
unsaturated carbonyl compounds using ((Ph3P)CuH)6.
Journal of the American Chemcial Society, 110, 291–293.
DOI: 10.1021/ja00209a048.
Monguchi, D., Beemelmanns, C., Hashizume, D., Hamashima,
Y.,
&
Sodeoka, M. (2008). Catalytic asymmetric con-
more reactive system
jugate reduction with ethanol:
A
Pd(II)–iPr–DUPHOS complex with molecular sieves 4A.
Journal of Organometallic Chemistry, 693, 867–873. DOI:
10.1016/j.jorganchem.2007.10.005.
Mori, A., Fujita, A., Nishihara, Y., & Hiyama, T. (1997). Cop-
per(I) salt mediated 1,4-reduction of α,β-unsaturated ke-
tones using hydrosilanes. Chemical Communications, 1997,
2159–2160. DOI: 10.1039/a706032g.
Mori, A., Fujita, A., Kajiro, H., Nishihara, Y., & Hiyama,
T. (1999). Conjugate reduction of α,β-unsaturated ketones
with hydrosilane mediated by copper(I) salt. Tertahedron,
55, 4573–4582. DOI: 10.1016/s0040-4020(99)00141-6.
Moser, R., Boškovi´c, Ž. V., Crowe, C. S., & Lipshutz, B. H.
(2010). CuH-catalyzed enantioselective 1,2-reductions of α,β-