Journal of the American Chemical Society
Communication
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Replacing the benzoate counterion with chloride suppressed
both oxidation and dehydroformylation (Scheme 4a,b). In the
absence of DMAA, dehydrogenation of alcohol 1w was not
observed (Scheme 4a). In contrast, decarbonylation of
aldehyde 11 gave ethylbenzene 3c (78% yield, 5.5:1 3c:2c,
Scheme 4b). These observations highlight the importance of
both the benzoate counterion and DMAA. In support of the
protonation of intermediate E (Scheme 3), we observed
deuterium incorporation at the β-position of DMAA when
using deuterated isopropanol 12-d1 (Scheme 4c). Hydrogen−
deuterium exchange is possible during dehydroformylation via
the benzoate counterion acting as a proton shuttle (Scheme
4c,d).5a Moreover, no evolution of H2 (g) was observed using
GC-TCD.
Using competition experiments, we studied the chemo-
selectivity of this cascade (Scheme 2, see SI for details).
Aldehydes undergo dehydroformylation in preference to
primary alcohols undergoing oxidative dehydroxymethylation,
with 60:1 selectivity. Primary alcohols oxidize faster than
secondary, and benzylic alcohols faster than aliphatic. These
observations support that alcohol oxidation is the turnover
limiting cycle in this novel cascade.
Established strategies for constructing olefins, including the
Wittig olefination,18 the Heck reaction,19 and olefin meta-
thesis,20 generate carbon−carbon bonds. In contrast, our
strategy contributes to emerging routes to olefins that involve
C−C bond cleavage.21 These methods represent examples of a
one-carbon dehomologation of carbon frameworks and thus
hold promise for various applications, including the conversion
of biomass into feedstocks.22 Moreover, such transformations
increase retrosynthetic flexibility by allowing the interconver-
sion of two common functional groups.14
(7) Wang, D.; Astruc, D. Chem. Rev. 2015, 115, 6621.
(8) For examples of using alcohols as surrogates for aldehydes, see:
(a) Kim, S. W.; Zhang, W.; Krische, M. J. Acc. Chem. Res. 2017, 50,
2371. For select examples, see: (b) Lebel, H.; Paquet, V. J. Am. Chem.
Soc. 2004, 126, 11152. (c) Xie, X.; Stahl, S. S. J. Am. Chem. Soc. 2015,
137, 3767. (d) Zultanski, S. L.; Zhao, J.; Stahl, S. S. J. Am. Chem. Soc.
2016, 138, 6416. (e) Liang, T.; Woo, S. K.; Krische, M. J. Angew.
Chem., Int. Ed. 2016, 55, 9207.
ASSOCIATED CONTENT
* Supporting Information
The Supporting Information is available free of charge on the
■
S
Detailed experimental procedures and compound
(9) For a definition of tandem catalysis, see: Fogg, D. E.; dos Santos,
E. N. Coord. Chem. Rev. 2004, 248, 2365.
(10) The reverse process is possible. For selected examples of olefin
tandem hydroformylation-hydrogenation, see: (a) Takahashi, K.;
Yamashita, M.; Ichihara, T.; Nakano, K.; Nozaki, K. Angew. Chem., Int.
Ed. 2010, 49, 4488. (b) Boogaerts, I. I. F.; White, D. F. S.; Cole-
Hamilton, D. J. Chem. Commun. 2010, 46, 2194. (c) Fuchs, D.;
Rousseau, G.; Diab, L.; Gellrich, U.; Breit, B. Angew. Chem., Int. Ed.
̈
2012, 51, 2178. (d) Diebolt, O.; Muller, C.; Vogt, D. Catal. Sci.
Technol. 2012, 2, 773. (e) Takahashi, K.; Yamashita, M.; Nozaki, K. J.
Am. Chem. Soc. 2012, 134, 18746.
AUTHOR INFORMATION
Corresponding Author
ORCID
■
Author Contributions
†X.W. and F.A.C. contributed equally.
(11) We observe transfer hydroformylation and hydrogenation of A2
and A3. We observe only transfer hydrogenation of the other
acceptors in Table 1. For DMAA as a transfer hydrogenation acceptor,
see: Mai, V. H.; Nikonov, G. I. Organometallics 2016, 35, 943.
(12) For an example of Rh-catalyzed decarbonylation in refluxing
acetone (∼60 °C), see: Bergens, S. H.; Fairlie, D. P.; Bosnich, B.
Organometallics 1990, 9, 566.
(13) For decarbonylation of allylic alcohols to give R−H, see:
Emery, A.; Oehlschlager, A. C.; Unrau, A. M. Tetrahedron Lett. 1970,
11, 4401.
(14) Breakthroughs in olefin synthesis by dehomologation have been
achieved from carboxylic acid derivatives. Carboxylic acids:
(a) Gooβen, L. J.; Rodríguez, N. Chem. Commun. 2004, 40, 724.
(b) Liu, Y.; Kim, K. E.; Herbert, M. B.; Fedorov, A.; Grubbs, R. H.;
Stoltz, B. M. Adv. Synth. Catal. 2014, 356, 130. (c) Liu, Y.; Virgil, S.
C.; Grubbs, R. H.; Stoltz, B. M. Angew. Chem., Int. Ed. 2015, 54,
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
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Funding was provided by the National Science Foundation
(CHE-1465263), the National Institutes of Health
(R35GM127071), UC Irvine, and Chevron Phillips. F.A.C. is
grateful for an NSF Graduate Research Fellowship. We thank
Steven M. Bischoff (Chevron Phillips) and Daniel H. Ess
(Brigham Young) for discussion, as well as Yang Lab (UC
Irvine) for their help with GC studies.
REFERENCES
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