Diene hydroaminomethylation via ruthenium-catalyzed C-C bond forming transfer hydrogenation: Beyond carbonylation

Article abstract of DOI:10.1039/c5sc03854e

Under the conditions of ruthenium catalyzed transfer hydrogenation using 2-propanol as terminal reductant, 1,3-dienes engage in reductive C-C coupling with formaldimines obtained in situ from 1,3,5-tris(aryl)-hexahydro-1,3,5-triazines to form homoallylic amines. Deuterium labelling studies corroborate a mechanism involving reversible diene hydroruthenation to form an allylruthenium complex that engages in turn-over limiting imine addition. Protonolysis of the resulting amidoruthenium species releases product and delivers a ruthenium alkoxide, which upon β-hydride elimination closes the catalytic cycle. These transformations, which include enantioselective variants, represent the first examples of diene hydroaminomethylation.

Full text of DOI:10.1039/c5sc03854e

Chemical
Science
View Article Online
View Journal
EDGE ARTICLE
Diene hydroaminomethylation via ruthenium-
catalyzed C–C bond forming transfer
hydrogenation: beyond carbonylation†
Cite this: DOI: 10.1039/c5sc03854e
*
Susumu Oda, Jana Franke and Michael J. Krische
Under the conditions of ruthenium catalyzed transfer hydrogenation using 2-propanol as terminal
reductant, 1,3-dienes engage in reductive C–C coupling with formaldimines obtained in situ from 1,3,5-
tris(aryl)-hexahydro-1,3,5-triazines to form homoallylic amines. Deuterium labelling studies corroborate
a mechanism involving reversible diene hydroruthenation to form an allylruthenium complex that
engages in turn-over limiting imine addition. Protonolysis of the resulting amidoruthenium species
releases product and delivers a ruthenium alkoxide, which upon b-hydride elimination closes the
catalytic cycle. These transformations, which include enantioselective variants, represent the first
examples of diene hydroaminomethylation.
Received 11th October 2015
Accepted 2nd November 2015
DOI: 10.1039/c5sc03854e
www.rsc.org/chemicalscience
discovery at BASF in 1949 by Reppe,4 hydroaminomethylation
initially received only a modest level of attention from academic
and industrial researchers.5 The systematic studies of Eilbracht
in the late 1990’s6 brought rhodium catalyzed hydro-
aminomethylation to the forefront of research, and in the last
15 years signicant progress in this area was made. Notable
achievements include the design of catalytic systems enabling
direct use of ammonia,6c,7 the ability to control regioselectivity
in reactions of terminal8a as well as internal8b alkenes via ligand
control8 or use of directing groups,9 and the development of the
Introduction
Rhodium catalyzed hydroformylation-reductive amination or
“hydroaminomethylation”1 of a-olens (Scheme 1, eqn (1)) has
emerged as an important method for the synthesis of N-con-
taining compounds, including pharmaceutical ingredients (e.g.
cinacalcet,2,3a ibutilide,2,3b and fexofenadine2,3c). Following its
rst
ruthenium
catalyzed
carbonylative
hydroaminomethylations.10
Despite these advances, existing catalysts for hydro-
aminomethylation via hydroformylation-reductive amination
are restricted to the use of nonconjugated alkenes, typically a-
olens. The carbonylative hydroaminomethylation of other p-
unsaturated reactants, such as 1,3-dienes, has not been re-
ported, as regioselectivity and “over-hydroformylation” to form
dialdehydes are difficult to control (Scheme 1, eqn (2)).11 In
connection with our exploration of hydrogenation and transfer
hydrogenation in the context of reductive C–C coupling, we have
found that paraformaldehyde serves as a convenient and inex-
pensive C1-building block for the hydrohydroxymethylation of
1,3-dienes,12 allenes13,14 and alkynes.15 Most importantly,
reductive couplings of paraformaldehyde provide access to
products of hydrohydroxymethylation that cannot be formed
selectively under hydroformylation conditions.16
Scheme 1 Hydroaminomethylation via carbonylation or 2-propanol
mediated reductive coupling.
These results supported the feasibly of corresponding
hydroaminomethylations wherein p-unsaturated reactants are
reductively coupled with formaldimines. In proof-of-concept
studies, it was found that 1,1-disubstituted allenes engage in
regioselective reductive coupling with formaldimines derived in
situ through cracking of 1,3,5-tris(aryl)-hexahydro-1,3,5-
Department of Chemistry, University of Texas at Austin, Austin, Texas, 78712 USA.
E-mail: mkrische@mail.utexas.edu
† Electronic supplementary information (ESI) available: Experimental procedures
and spectral data for new compounds, including scanned images of 1H and 13C
NMR spectra. Single crystal X-ray diffraction data for a derivative of 5a. CCDC
1430833. For ESI and crystallographic data in CIF or other electronic format see
DOI: 10.1039/c5sc03854e
This journal is © The Royal Society of Chemistry 2015
Chem. Sci.

View Article Online
Chemical Science
Edge Article
triazines under the conditions of ruthenium catalyzed transfer of the monodentate phosphine ligands, for example PCy3 (Table
hydrogenation employing 2-propanol as terminal reductant.17 1, entry 2). A series of chelating bis(diphenylphosphino)-
Corresponding hydroaminomethylations of 1,3-dienes such as substituted ligands were screened, including dppf, dppm and
butadiene, isoprene and myrcene, which are important feed- dppe (Table 1, entries 3–5). The isolated yield of 3a was
stock chemicals, would be even more desirable, however, increased to 81% using dppe, however, substantial quantities of
competing aza-Diels–Alder cycloaddition18 and alkene isomeri- olen isomerization product, allylic amine iso-3a, was formed
zation19 of the homoallylic amines products rendered the (Table 1, entry 5).19 The chelating ligands dCypm and dCype,
outcome of such processes uncertain. Here, we report that which incorporate bis(dicyclohexylphosphino) moieties,
ruthenium complexes modied by dCypm (bis(dicyclohex- provided superior results, delivering the homoallylic amine 3a
ylphosphino)methane) catalyze the 2-propanol mediated in 86% (10 : 1, 3a : iso-3a) and 71% (20 : 1, 3a : iso-3a) isolated
reductive coupling of 2-substituted 1,3-dienes with 1,3,5- yields, respectively (Table 1, entries 6 and 7). Attempts to
tris(aryl)-hexahydro-1,3,5-triazines to form products of hydro- enhance the performance of the dCypm-modied catalyst
aminomethylation as single regioisomers with complete through variation of reaction temperature (Table 1, entries 8
suppression of olen isomerization in all but one case (Scheme and 9) or reaction time (Table 1, entry 10) did not avail addi-
1, eqn (3)). These transformations represent the rst examples tional improvement (Table 2).
of diene hydroaminomethylation.20,21
An attempt was made to apply these optimal conditions
(Table, entry 6) to a series of 2-substituted 1,3-dienes 1b–1i,
ꢀ
however, at 120 C the desired products 3b–3i were accompa-
Results and discussion
nied by signicant quantities of the corresponding aza-Diels–
Hexahydro-1,3,5-triazine 2a is a white, crystalline solid conve- Alder [4 + 2] cycloadducts.18 2-Substituted dienes display an
niently prepared through the condensation of para- enhanced conformational preference for the s-cis conformer,
formaldehyde and para-anisidine.22 In an initial experiment, which increases their rate of Diels–Alder cycloaddiꢀtion relative
butadiene 1a was exposed to hexahydro-1,3,5-triazine 2a in the to butadiene. At slightly higher temperatures (140 C in xylene
presence of 2-propanol (400 mol%) and commercial solvent), competing Diels–Alder reaction decelerates with
HClRu(CO)(PPh3)3 (5 mol%) in toluene solvent (0.5 M) at 120 ꢀC. respect to hydroaminomethylation and could be completely
The targeted product of hydroaminomethylation 3a was ob- suppressed. Using these slightly modied conditions, 2-
tained as a single isomer in 11% yield (Table 1, entry 1). A series substituted 1,3-dienes 1b–1i were reacted with hexahydro-1,3,5-
of phosphine ligands were evaluated for their ability to enhance triazine 2a to furnish the products of hydroaminomethylation
conversion. The isolated yield of 3a was not improved upon use 3b–3i in good yield as single regioisomers, and isomeric allylic
amines iso-3b–3i were not observed. Notably, a range of
substituents are tolerated at the 2-position of the diene,
Table 1 Selected optimization experiments in the ruthenium cata-
lyzed hydroaminomethylation of butadiene 1a via 2-propanol medi-
ated transfer hydrogenationa
including branched aliphatic moieties (1d, 1f), groups with
allylic heteroatoms (1d, 1e) and aryl groups (1g–1i). Under the
present conditions, 1-substituted dienes engage in reductive
coupling, however, lower conversions and selectivities were
observed. To illustrate the utility of homoallylic amines 3a–3i,
the hydroaminomethylation product 3b was transformed into
the trisubstituted piperidine 4b via Prins reaction with glyoxylic
acid mono-hydrate (Scheme 2, eqn (1)).23 Additionally, adduct 3i
was subjected to N-allylation and ring closing metathesis to
form the disubstituted piperidine 4i (Scheme 2, eqn (2)).24
Variation of the 1,3,5-tris(aryl)-hexahydro-1,3,5-triazine was
subsequently investigated in the hydroaminomethylation of
butadiene 1a (Table 3). N-Aryl substituted triazines 2a–2f were
subjected to optimal conditions identied for the hydro-
aminomethylation of butadiene using triazine 2a (Table 1, entry
6). Electron rich N-aryl triazines 2a–2c, including ortho-
substituted triazine 2c, undergo hydroaminomethylation effi-
ciently to afford the branched homoallylic amines 3a–5a with
complete regiocontrol. In each case, small quantities of the
allylic amines iso-3a–5a were observed as side-products. Elec-
tron neutral triazine 2d and electron decient triazines 2e and
2f were converted to the respective homoallylic amines 6a, 7a
and 8a in good yield, although increased quantities of the allylic
amine side-products were observed. As illustrated in the
formation of 8a, nitrogen bearing heterocycles are tolerated.
Attempted use of N-alkyl, N-acyl and N-sulfonyl triazines failed
Entry
Ligand
T (ꢀC)
Time (h)
Yield 3a
3a : iso-3a
1
—
PCy3
dppf
dppm
dppe
dCypm
dCype
dCypm
dCypm
dCypm
120
120
120
120
120
120
120
110
140
120
24
24
24
24
24
24
24
24
24
12
11%
10%
19%
34%
81%
86%
71%
65%
82%
74%
>20 : 1
>20 : 1
>20 : 1
4 : 1
2b
3
4
5
6
7
8
9
10
4 : 1
10 : 1
20 : 1
10 : 1
8 : 1
10 : 1
a
Yields are of material isolated by silica gel chromatography. Isomeric
ratios were determined via 1H NMR analysis. PMP
¼
para-
methoxyphenyl, dppf (1,10-bis(diphenylphosphino)ferrocene), dppm
(bis(diphenylphosphino)methane), dppe (1,2-bis(diphenylphosphino)
ethane), dCypm (bis(dicyclohexylphosphino)methane), dCype (1,2-
b
bis(dicyclohexylphosphino)ethane). PCy3 (10 mol%). See ESI† for
further details.
Chem. Sci.
This journal is © The Royal Society of Chemistry 2015

View Article Online
Edge Article
Chemical Science
Table 2 Ruthenium catalyzed hydroaminomethylation of 1,3-dienes
1a–1i to form homoallylic amines 3a–3i via 2-propanol mediated
transfer hydrogenationa
Entry
1b
1,3-Diene
Product
Yield (3 : iso-3)
86% yield
10 : 1 (3a : iso-3a)
Scheme 2 Conversion of hydroaminomethylation products 3b and 3i
to compounds 4b and 4i, respectively. aYields are of material isolated
by silica gel chromatography. (a) (HO)2CCO2H, MeCN–H2O, 25 ꢀC,
80% yield, 10 : 1 dr (b) BrCH2CH]CH2, K2CO3, DMF, 25 ꢀC, 75% yield.
(c) Grubbs-II, DCM, 40 ꢀC, 72% yield. See ESI† for further experimental
details.
79% yield
>20 : 1 (3b : iso-3b)
2
3
76% yield
>20 : 1 (3c : iso-3c)
in reactions of butadiene 1a. A survey of triazines 2a–2f revealed
that triazine 2c derived from ortho-anisidine provided the
highest levels of enantiomeric enrichment. Among various
chiral phosphine ligands, (R)-MeO-furyl-BIPHEP provided the
highest levels of enantiocontrol. In the presence of this chiral
ligand, the reaction of 1,3-butadiene 1a with N-ortho-methox-
yphenyl triazine 2c delivered the homoallylic amine 5a in 49%
yield as a 94 : 6 ratio of enantiomers in the absence of allylic
amine side-product iso-5a (Scheme 3). Application of these
initially developed conditions for enantioselective hydro-
aminomethylation to isoprene resulted in the formation of
homoallylic amine 5b in 54% yield as a 93 : 7 ratio of
71% yield, 2 : 1 dr
>20 : 1 (3d : iso-3d)
4
5
74% yield
>20 : 1 (3e : iso-3e)
70% yield
>20 : 1 (3f : iso-3f)
6
7
77% yield
>20 : 1 (3g : iso-3g)
Table 3 Ruthenium catalyzed hydroaminomethylation of butadiene
1a with 1,3,5-tris(aryl)-hexahydro-1,3,5-triazines 2a–2f to form
homoallylic amines 3a–8aa
72% yield
>20 : 1 (3h : iso-3h)
8
81% yield
>20 : 1 (3i : iso-3i)
9
a
Yields are of material isolated by silica gel chromatography. Isomeric
ratios were determined via 1H NMR analysis. b PhMe (0.5 M), 120 ꢀC. See
ESI† for further experimental details.
in the coupling with dienes under these initially developed
conditions. It should be noted that the 3a–8a : iso-3a–8a ratio
does not change as a function of conversion or reaction time,
suggesting olen isomerization is kinetically controlled,
perhaps occurring by way of the homoallylic amidoruthenium
intermediate (vida supra).
a
Yields are of material isolated by silica gel chromatography. Isomeric
Having established favourable conditions for diene hydro-
aminomethylation, enantioselective variants were investigated
ratios were determined via 1H NMR analysis. See ESI† for further
experimental details.
This journal is © The Royal Society of Chemistry 2015
Chem. Sci.

View Article Online
Chemical Science
Edge Article
Scheme
3
Enantioselective
ruthenium
catalyzed
hydro-
aminomethylation of butadiene 1a and isoprene 1b. aYields are of
material isolated by silica gel chromatography. Enantiomeric ratios
were determined by chiral stationary phase HPLC analysis. bXylene (0.5
M), 140 ꢀC. See ESI† for further experimental details.
enantiomers (Scheme 3). The absolute stereochemical assign-
ment of 5a was determined by single crystal X-ray diffraction
analysis of the corresponding 4-nitrobenzenesulfonamide.
Mechanistic studies
Scheme
5
General mechanism for ruthenium catalyzed diene
To illuminate key features of the catalytic mechanism, deute-
rium labelling studies of the ruthenium catalyzed hydro-
aminomethylation of isoprene 1b were performed (Scheme 4).
Hydroaminomethylation of isoprene 1b using the deuterated
triazine deuterio-2a provided deuterio-3b with complete reten-
tion of deuterium at the methylene carbon bearing nitrogen
hydroaminomethylation via transfer hydrogenation.
incorporation. Adventitious water also may diminish the extent
of deuterium incorporation.25
Guided by these data, a mechanism for ruthenium catalyzed
diene hydroaminomethylation via transfer hydrogenation was
proposed (Scheme 5). Diene hydroruthenation delivers a nucle-
ophilic allylruthenium complex. The stoichiometric reaction of
HXRu(CO)(PPh3)3 (X ¼ Cl, Br) with dienes (or allenes) to form p-
allylruthenium complexes has been reported.26 In the case of
isoprene 1b,26a cis-stereochemistry between the methyl groups
of the resulting p-allyl are observed. Notably, HClRu(CO)(PPh3)3
hydrometalates 1,1-dimethylallene to initially form a 1,1-
dimethyl substituted p-allylruthenium complex that rearranges
to the cis-1,2-dimethyl substituted p-allylruthenium complex,26c
suggesting cis-stereochemistry represents a thermodynamic
2
(>95% H). Deuterium was not detected at any other position.
This experiment suggests deuterio-3b is inert with respect to
amine dehydrogenation under these conditions. In a second
experiment, isoprene 1b was subjected to hydro-
aminomethylation using triazine 2a in the presence of d8-2-
propanol. As anticipated, the product deuterio-3b incorporates
signicant quantities of deuterium at the methyl group (65%
2H). However, deuterium also is incorporated at the terminal
vinylic positions (21% 2H) and, to a lesser extent, the allylic
2
position (10% H). These data corroborate a scenario wherein
rapid, reversible and non-regioselective diene hydrometalation
occurs in advance of turn-over limiting imine addition.
Reversible hydrometalation accounts for incomplete deuterium
rather than kinetic preference. Intervention of
a single
geometrical isomer at the stage of the s-allylruthenium inter-
mediate and ensuing transition state for imine addition
appears consistent with the relatively high levels of enantiose-
lectivity observed in the asymmetric hydroaminomethylation of
isoprene (Scheme 3). Protonolytic cleavage of the amidor-
uthenium complex derived upon imine addition mediated by
isopropanol releases the product of hydroaminomethylation 3b
and regenerates the ruthenium hydride to close the catalytic
cycle.
Conclusion
In summary, using the concepts of redox-triggered C]X (X ¼ O,
N) addition,27 we report the rst examples of diene hydro-
aminomethylation, including asymmetric variants. Specically,
ruthenium catalyzed transfer hydrogenation of 1,3-dienes in the
presence of tris(aryl)-hexahydro-1,3,5-triazines results in diene–
formaldimine reductive coupling to deliver homoallylic amines
in good yield with complete levels of regioselectivity. While
Scheme 4 Deuterium labelling studies of the ruthenium catalyzed
hydroaminomethylation of isoprene 1b. aYields are of material isolated
by silica gel chromatography. bXylene (0.5 M), 140 ꢀC. See ESI† for
further experimental details.
Chem. Sci.
This journal is © The Royal Society of Chemistry 2015

View Article Online
Edge Article
Chemical Science
further optimization is required to enhance performance, these
processes dene an alternative to classical carbonylative
hydroaminomethylation via hydroformylation-reductive ami-
nation, which is presently limited to reactions of non-
conjugated olens. More broadly, these studies contribute to
an ever-growing body of catalytic C–C bond formations that
merge the characteristics of carbonyl and imine addition with
transfer hydrogenation.27
E. E. MacEntire and J. F. Knion, (Texaco Development
Corp.) EP 240193, 1987transChem. Abstr., 1989, 110,
134785h; (k) M. D. Jones, J. Organomet. Chem., 1989, 366,
403; (l) E. Drent and A. J. M. Breed, (Shell Int. Res. M.) EP
457386, 1992transChem. Abstr., 1992, 116, 83212h; (m)
¨ ¨
´
´
´
S. Toros, I. Gemes-Pesci, B. Heil, S. Maho and Z. Tuba, J.
Chem. Soc., Chem. Commun., 1992, 858; (n) T. Baig and
P. Kalck, J. Chem. Soc., Chem. Commun., 1992, 1373; (o)
T. Baig, J. Molinier and P. Kalck, J. Organomet. Chem.,
1993, 455, 219; (p) G. Diekhaus, D. Kampmann, C. Kniep,
Acknowledgements
¨
T. Muller, J. Walter and J. Weber, (Hoechst AG) DE
The Robert A. Welch Foundation (F-0038), the NSF (CHE-
1265504) and the University of Texas Center for Green Chem-
istry and Catalysis are acknowledged for partial support of this
research. The Deutsche Forschungsgemeinscha (DFG) post-
doctoral fellowship program (FR 3555/1-1) is acknowledged for
partial support (J.F.).
4334809, 1993transChem. Abstr., 1995, 122, 314160g; (q)
J. J. Brunet, D. Neibecker, F. Agbossou and R. S. Srivastava,
J. Mol. Catal., 1994, 87, 223; (r) M. Beller, B. Cornils,
C. D. Frohning and C. W. Kohlpainter, J. Mol. Catal. A:
Chem., 1995, 104, 17.
6 (a) T. Rische and P. Eilbracht, Synthesis, 1997, 1331; (b)
C. L. Kranemann and P. Eilbracht, Synthesis, 1998, 71; (c)
T. Rische, B. Kitsos-Rzychon and P. Eilbracht, Tetrahedron,
Notes and references
¨
1998, 54, 2723; (d) L. Barfacker, C. Hollmann and
1 For selected reviews on hydroaminomethylation, see: (a)
P. Eilbracht, Tetrahedron, 1998, 54, 4493; (e) T. Rische and
¨
¨
P. Eilbracht, L. Barfacker, C. Buss, C. Hollmann,
P. Eilbracht, Tetrahedron, 1998, 54, 8441; (f) L. Barfacker,
B. E. Kitsos-Rzychon, C. L. Kranemann, T. Rishe,
R. Roggenbuck and A. Schmidt, Chem. Rev., 1999, 99, 3329;
(b) B. Breit and W. Seiche, Synthesis, 2001, 1; (c)
P. Eilbracht and A. M. Schmidt, Top. Organomet. Chem.,
2006, 18, 65; (d) D. Crozet, M. Urrutigoity and P. Kalck,
ChemCatChem, 2011, 3, 1102; (e) A. Behr and A. J. Vorholt,
D. El Tom and P. Eilbracht, Tetrahedron Lett., 1999, 40,
4031; (g) C. L. Kranemann, B. Costisella and P. Eilbracht,
¨
Tetrahedron Lett., 1999, 40, 7773; (h) T. Rische, L. Barfacker
and P. Eilbracht, Eur. J. Org. Chem., 1999, 653; (i)
¨
P. Eilbracht, C. L. Kranemann and L. Barfacker, Eur. J. Org.
Chem., 1999, 1907; (j) T. Rische and P. Eilbracht,
Tetrahedron, 1999, 55, 1915; (k) T. Rische and P. Eilbracht,
Tetrahedron, 1999, 55, 3917; (l) C. L. Kranemann,
B. E. Kitsos-Rzychon and P. Eilbracht, Tetrahedron, 1999,
Top.
Organomet.
Chem.,
2012,
39,
103;
(f)
S. Raoufmoghaddam, Org. Biomol. Chem., 2014, 12, 7179;
(g) X.-F. Wu, X. Fang, L. Wu, R. Jackstell, H. Neumann and
M. Beller, Acc. Chem. Res., 2014, 47, 1041.
¨
55, 4721; (m) L. Barfacker, T. Rische and P. Eilbracht,
¨
2 R. Franke, D. Selent and A. Borner, Chem. Rev., 2012, 112,
Tetrahedron, 1999, 55, 7177; (n) T. Rische and P. Eilbracht,
¨
5675.
Tetrahedron, 1999, 55, 7841; (o) T. Rische, K.-S. Muller and
3 (a) O. Thiel, C. Bernard, R. Larsen, M. J. Martinelli and
M. T. Raza, (Amgen Inc.) WO Patent 2009002427,
2008transChem. Abstr., 2007, 71, 12990; (b) J. R. Briggs,
J. Klosin and G. T. Whiteker, Org. Lett., 2005, 7, 4795; (c)
G. Whiteker, Top. Catal., 2010, 53, 1025.
4 Reppe’s pioneering studies employ near stoichiometric
loadings of Fe(CO)5: (a) W. Reppe, Experientia, 1949, 5, 93;
(b) W. Reppe and H. Vetter, Liebigs Ann. Chem., 1953, 582,
133.
P. Eilbracht, Tetrahedron, 1999, 55, 9801; (p)
C. L. Kranemann and P. Eilbracht, Eur. J. Org. Chem., 2000,
2367; (q) A. Behr, M. Fiene, C. Buss and P. Eilbracht, Eur. J.
Lipid Sci. Technol., 2000, 102, 467.
7 (a) B. Zimmermann, J. Herwig and M. Beller, Angew. Chem.,
Int. Ed., 1999, 38, 2372; (b) B. Zimmermann, J. Herwig and
M. Beller, Chem. Ind., 2001, 82, 521; (c) H. Klein,
R. Jackstell, M. Kant, A. Martin and M. Beller, Chem. Eng.
Technol., 2007, 30, 721.
5 (a) H. de V. Finch and R. E. Meeker, (Shell Oil Company) US
Pat., 3234283, 1966transChem. Abstr., 1965, 62, 14500b; (b)
G. Biale, (Union Oil Company) US Pat., 3513200,
1970transChem. Abstr., 1970, 73, 34776a; (c) A. F. M. Iqbal,
Helv. Chim. Acta, 1971, 54, 1440; (d) T. Imai, (Uop Inc.) US.
8 (a) M. Ahmed, A. M. Seayad, R. Jackstell and M. Beller, J. Am.
Chem. Soc., 2003, 125, 10311; (b) M. Ahmed, R. P. J. Bronger,
R. Jackstell, P. C. J. Kamer, P. W. N. M. van Leeuwen and
M. Beller, Chem.–Eur. J., 2006, 12, 8979.
9 B. Breit, Tetrahedron Lett., 1998, 39, 5163.
Pat., 4220764, 1978transChem. Abstr., 1980, 93, 239429d; (e) 10 L. Wu, I. Fleischer, R. Jackstell and M. Beller, J. Am. Chem.
R. M. Laine, J. Org. Chem., 1980, 45, 3370; (f)
Soc., 2013, 135, 3989.
F. Jachimowicz, (W. R. Grace and Co.) Belgian Patent 11 For selected examples of 1,3-diene hydroformylation, see: (a)
887630, 1980transChem. Abstr., 1981, 95, 152491k; (g)
F. Jachimowicz and J. W. Raksis, J. Org. Chem., 1982, 47,
445; (h) K. Murata, A. Matsuda and T. Masuda, J. Mol.
Catal., 1984, 23, 121; (i) F. Jachimowicz and P. Manson,
(W. R. Grace and Co.) Canadian Patent 123 1199,
W. H. Clement and M. Orchin, Ind. Eng. Chem. Prod. Res.
Dev., 1965, 4, 283; (b) B. Fell and H. Bahrmann, J. Mol.
Catal., 1977, 2, 211; (c) H. Bahrmann and B. Fell, J. Mol.
Catal., 1980, 8, 329; (d) C. Botteghi, M. Branca and A. Saba,
J. Organomet. Chem., 1980, 184, C17–C19; (e)
P. W. N. M. van Leeuwen and C. F. Roobeek, J. Mol. Catal.,
1984transChem.
Abstr.,
1988,
109,
38485u;
(j)
This journal is © The Royal Society of Chemistry 2015
Chem. Sci.

View Article Online
Chemical Science
Edge Article
1985, 31, 345; (f) J. C. Chalchat, R. Ph. Garry, E. Lecomte and
A. Michet, Flavour Fragrance J., 1991, 6, 179; (g) S. Bertozzi,
N. Campigli, G. Vitulli, R. Lazzaroni and P. Salvadori, J.
Organomet. Chem., 1995, 487, 41; (h) T. Horiuchi, T. Ohta,
K. Nozaki and H. Takaya, Chem. Commun., 1996, 155; (i)
Tetrahedron Lett., 2002, 43, 1839; (b) T. J. Donohoe,
T. J. C. O’Riordan and C. P. Rosa, Angew. Chem., Int. Ed.,
2009, 48, 1014; (c) C. R. Larsen and D. B. Grotjahn, J. Am.
Chem. Soc., 2012, 134, 10357; (d) J. R. Clark, J. R. Griffiths
and S. T. Diver, J. Am. Chem. Soc., 2013, 135, 3327.
T. Horiuchi, T. Ohta, E. Shirakawa, K. Nozaki and 20 For nickel catalyzed diene–imine reductive couplings and
H. Takaya, Tetrahedron, 1997, 53, 7795; (j) P. Liu and
E. N. Jacobsen, J. Am. Chem. Soc., 2001, 123, 10772; (k)
H. J. V. Barros, B. E. Hanson, E. N. dos Santos and
E. V. Gusevskaya, Appl. Catal., A, 2004, 278, 57; (l)
related multi-component processes, see: (a) M. Kimura,
A. Miyachi, K. Kojima, S. Tanaka and Y. Tamaru, J. Am.
Chem. Soc., 2004, 126, 14360; (b) K. Kojima, M. Kimura
and Y. Tamaru, Chem. Commun., 2005, 4717; (c)
M. Kimura, K. Kojima, Y. Tatsuyama and Y. Tamaru, J. Am.
Chem. Soc., 2006, 128, 6332; (d) M. Kimura, Y. Tatsuyama,
K. Kojima and Y. Tamaru, Org. Lett., 2007, 9, 1871.
˜
H. J. V. Barros, J. G. da Silva, C. C. Guimaraes, E. N. dos
Santos and E. V. Gusevskaya, Organometallics, 2008, 27,
4523; (m) A. L. Watkins and C. R. Landis, Org. Lett., 2011,
13, 164; (n) T. E. Smith, S. J. Fink, Z. G. Levine, 21 For the ruthenium catalyzed C–C coupling of 1,3-dienes with
K. A. McClelland, A. A. Zackheim and M. E. Daub, Org.
Lett., 2012, 14, 1452.
12 For catalytic reductive coupling of 1,3-dienes with
paraformaldehyde, see: (a) T. Smejkal, H. Han, B. Breit
and M. J. Krische, J. Am. Chem. Soc., 2009, 131, 10366; (b)
carbonyl partners or imines, see: (a) F. Shibahara, J. F. Bower
and M. J. Krische, J. Am. Chem. Soc., 2008, 130, 6338; (b)
J. R. Zbieg, E. Yamaguchi, E. L. McInturff and
M. J. Krische, Science, 2012, 336, 324; (c) S. Zhu, X. Lu,
Y. Luo, W. Zhang, H. Jiang, M. Yan and W. Zeng, Org. Lett.,
2013, 15, 1440; (d) T.-Y. Chen, R. Tsutsumi,
T. P. Montgomery, I. Volchkov and M. J. Krische, J. Am.
Chem. Soc., 2015, 137, 1798.
¨
A. Kopfer, B. Sam, B. Breit and M. J. Krische, Chem. Sci.,
2013, 4, 1876.
13 For catalytic reductive coupling of allenes to
paraformaldehyde, see: (a) M.-Y. Ngai, E. Skucas and 22 (a) C. A. Bischoff and F. Reinfeld, Chem. Ber., 1903, 36, 41; (b)
M. J. Krische, Org. Lett., 2008, 10, 2705; (b) B. Sam,
T. P. Montgomery and M. J. Krische, Org. Lett., 2013, 15,
3790.
A. G. Giumanini, G. Verardo, E. Zangrando and L. Lassiani, J.
Prakt. Chem., 1987, 329, 1087; (c) A. G. Giumanini,
N. Toniutti, G. Verardo and M. Merli, Eur. J. Org. Chem.,
1999, 141.
14 For catalytic redox-neutral coupling of allenes with
methanol, see: J. Moran, A. Preetz, R. A. Mesch and 23 D. J. Bennet and N. M. Hamilton, Tetrahedron Lett., 2000, 41,
M. J. Krische, Nat. Chem., 2011, 3, 287. 7961.
15 C. C. Bausch, R. L. Patman, B. Breit and M. J. Krische, Angew. 24 G. C. Vougioukalakis and R. H. Grubbs, Chem. Rev., 2010,
Chem., Int. Ed., 2011, 50, 5687. 110, 1746.
16 For a review on the use of paraformaldehyde and methanol 25 S. K. S. Tse, P. Xue, Z. Lin and G. Jia, Adv. Synth. Catal., 2010,
as C1-feedstocks in metal catalyzed C–C coupling, see: 352, 1512.
B. Sam, B. Breit and M. J. Krische, Angew. Chem., Int. Ed., 26 For the stoichiometric reaction of HXRu(CO)(PPh3)3 (X ¼ Cl,
2015, 53, 3267.
Br) with dienes or allenes to furnish p-allylruthenium
complexes, see: (a) K. Hiraki, N. Ochi, Y. Sasada,
H. Hayashida, Y. Fuchita and S. Yamanaka, J. Chem. Soc.,
Dalton Trans., 1985, 873; (b) A. F. Hill, C. T. Ho and
J. D. E. T. Wilton-Ely, Chem. Commun., 1997, 2207; (c)
P. Xue, S. Bi, H. H. Y. Sung, I. D. Williams, Z. Lin and
G. Jia, Organometallics, 2004, 23, 4735.
17 S. Oda, B. Sam and M. J. Krische, Angew. Chem., Int. Ed.,
2015, 54, 8525.
18 For selected examples of the thermal Diels–Alder [4 + 2]
cycloaddition of 1,3-dienes with formaldimines, see: (a)
S. D. Larsen and P. A. Grieco, J. Am. Chem. Soc., 1985, 107,
1768; (b) L. Bhat, A. G. Steinig, R. Appelbe and A. De
Meijere, Eur. J. Org. Chem., 2001, 1673.
27 J. M. Ketcham, I. Shin, T. P. Montgomery and M. J. Krische,
Angew. Chem., Int. Ed., 2014, 53, 9142.
19 For selected examples of ruthenium catalyzed alkene
isomerization, see: (a) C. Cadot, P. I. Dalko and J. Cossy,
Chem. Sci.
This journal is © The Royal Society of Chemistry 2015