Journal of the American Chemical Society
Page 4 of 5
1
2
ACS Catal. 2012, 2, 1993. (f) Oestreich, M.; Hartmann, E.; Mewald,
(10) Lewis base-catalyzed diboration involves formation of sp2–sp3
3
4
5
6
7
8
9
M. Chem. Rev. 2013, 133, 402.
hybridized diboron as a catalyst intermediate via nucleophilic attack
of the Lewis base to the boron center. See ref. 6 and 7. See also
following references that involve structurally characterized sp2–sp3
hybridized diboron: (a) Clegg, W.; Dai, C.; Lawlor, F. J.; Marder, T.
B.; Nguyen, P.; Norman, N. C.; Pickett, N. L.; Power, W. P.; Scott, A.
J. J. Chem. Soc., Dalton Trans. 1997, 839. (b) Gao, M.; Thorpe, S. B.;
Kleeberg, C.; Slebodnick, C.; Marder, T. B.; Santos, W. L. J. Org.
Chem. 2011, 76, 3997. (c) Kleeberg, C. K.; Crawford, A. G.;
Batsanov, A.; Hodgkinson, P.; Apperley, D. C.; Cheung, M. S.; Lin,
Z.; Marder, T. B. J. Org. Chem. 2012, 77, 785.
(11) (a) Oshima, K.; Ohmura, T.; Suginome, M. J. Am. Chem. Soc.
2011, 133, 7324; (b) Oshima, K.; Ohmura, T.; Suginome, M. J. Am.
Chem. Soc. 2012, 134, 3699.
(12) Oshima, K.; Ohmura, T.; Suginome, M. Chem. Commun. 2012,
48, 8571.
(13) Catalytic hydroboration of pyridines reported from other
groups: (a) Arrowsmith, M.; Hill, M. S.; Hadlington, T.; Kociok-
Köhn, G; Weetman, C. Organometallics 2011, 30, 5556. (b) Intemann,
J.; Lutz, M.; Harder, S. Organometallics 2014, 33, 5722. (c) Dudnik,
A. S.; Weidner, V. L.; Motta, A.; Delferro, M.; Marks, T. J. Nat.
Chem. 2014, 6, 1100. Transition-metal-free addition of Ph2P–B(pin)
to pyridine and acridine: (d) Daley, E. N.; Vogels, C. M.; Geier, S. J.;
Decken, A.; Doherty, S.; Westcott, S. A. Angew. Chem. Int. Ed. Early
View (DOI: 10.1002/anie.201410033).
(3) (a) Crabtree, R. H. The Organometallic Chemistry of the
Transition Metals, 2nd ed., John Wiley and Sons: New York, 1994.
(b) Hartwig, J. F. Organotransition Metal Chemistry, University
Science Books, California, 2010. For oxidative addition of B–B to
Rh(I) and Pt(0), see: (c) Ishiyama, T.; Matsuda, N.; Miyaura, N.;
Suzuki, A. J. Am. Chem. Soc. 1993, 115, 11018. (d) Nguyen, P.;
Lesley, G.; Taylor, N. J.; Marder, T. B.; Pickett, N. L.; Clegg, W.;
Elsegood, M. R. J.; Norman, N. C. Inorg. Chem. 1994, 33, 4623. (e)
Ishiyama, T.; Matsuda, N.; Murata, M.; Ozawa, F.; Suzuki, A.;
Miyaura, N. Organometallics 1996, 15, 713.
(4) (a) Chase, P. A.; Welch, G. C.; Jurca, T.; Stephan, D. W.
Angew. Chem. Int. Ed. 2007, 46, 8050. (b) Spies, P.; Schwendemann,
S.; Lange, S.; Kehr, G.; Fröhlich, R.; Erker, G. Angew. Chem. Int. Ed.
2008, 47, 7543. For recent reviews, see: (c) Stephan, D. W. Org.
Biomol. Chem. 2012, 10, 5740. (d) Stephan, D. W.; Erker, G. Top.
Curr. Chem. 2013, 332, 85. (e) Hounjet, L. J.; Stephan, D. W. Org.
Process Res. Dev. 2014, 18, 385. (f) Paradies, J. Angew. Chem. Int.
Ed. 2014, 53, 3552.
(5) t-BuOK-catalyzed hydrogenation of ketones with H2 has also
been reported. (a) Walling, C.; Bollyky, L. J. Am. Chem. Soc. 1961,
83, 2968. (b) Walling, C.; Bollyky, L. J. Am. Chem. Soc. 1964, 86,
3750. (c) Berkessel, A.; Schubert, T. J. S.; Müller, T. N. J. Am. Chem.
Soc. 2002, 124, 8693.
(6) (a) Bonet, A.; Pubill-Ulldemolins, C.; Bo, C.; Gulyás, H.;
Fernández, E. Angew. Chem. Int. Ed. 2011, 50, 7158. (b) Bonet, A.;
Sole, C.; Gulyás, H.; Fernández, E. Org. Biomol. Chem. 2012, 10,
6621. (c) Blaisdell, T. P.; Caya, T. C.; Zhang, L.; Sanz-Marco, A.;
Morken, J. P. J. Am. Chem. Soc. 2014, 136, 9264. (d) Miralles, N.;
Cid, J.; Cuenca, A. B.; Carbó, J. J.; Fernández, E. Chem. Commun.
2015, 51, 1693. For related diboration using stoichiometric amount of
an alkoxide, see: (e) Nagashima, Y.; Hirano, K.; Takita, R.; Uchiyama,
M. J. Am. Chem. Soc. 2014, 136, 8532. For t-BuOK-catalyzed
silaboration of styrenes, see: (f) Ito, H.; Horita, Y.; Yamamoto, E.
Chem. Commun. 2012, 48, 8006.
(7) α,β-Unsaturated carbonyl compounds and imines also undergo
addition of diboron under organocatalytic conditions, giving β-boryl
carbonyl compounds and α-boryl alkylamine derivatives, respectively.
(a) Lee, K.; Zhugralin, A. R.; Hoveyda, A. H. J. Am. Chem. Soc. 2009,
131, 7253 and J. Am. Chem. Soc. 2010, 132, 12766 (additions &
corrections); (b) Bonet, A.; Gulyás, H.; Fernández, E. Angew. Chem.
Int. Ed. 2010, 49, 5130. (c) Pubill-Ulldemolins, C.; Bonet, A.; Bo, C.;
Gulyás, H.; Fernández, E. Chem. Eur. J. 2012, 18, 1121. (d) Wu, H.;
Radomkit, S.; O’Brien, J. M.; Hoveyda, A. H. J. Am. Chem. Soc.
2012, 134, 8277. (e) Solé, C.; Gulyás, H.; Fernández, E. Chem.
Commun. 2012, 48, 3769. (f) Wen, K.; Chen, J.; Gao, F.; Bhadury, P.
S.; Fan, E.; Sun, Z. Org. Biomol. Chem. 2013, 11, 6350. (g) Cid, J.;
Carbó, J. J.; Fernández, E. Chem. Eur. J. 2014, 20, 3616. (h) Cascia,
E. L.; Sanz, X.; Bo, C.; Whiting, A.; Fernández, E. Org. Biomol.
Chem. 2015, 13, 1328.
(8) For reviews, see: (a) Cid, J.; Gulyás, H.; Carbó, J. J.; Fernández,
E. Chem. Soc. Rev. 2012, 41, 3558. (b) Gulyás, H.; Bonet, A.; Pubill-
Ulldemolins, C.; Solé, C.; Cid, J.; Fernández, E. Pure Appl. Chem.
2012, 84, 2219.
(9) FLP-catalyzed hydrogenation involves formation of a highly
polarized [H–LA]–[H–LB]+ species as a catalyst intermediate via
heterolytic cleavage of H–H bond (LA: Lewis acid; LB: Lewis base).
See ref. 4. Related organocatalytic activation of H–Si and H–B bonds:
(a) Parks, D. J.; Piers, W. E. J. Am. Chem. Soc. 1996, 118, 9440. (b)
Rendle, S.; Oestreich, M. Angew. Chem. Int. Ed. 2008, 47, 5997. (c)
Eisenberger, P.; Bailey, A. M.; Crudden, C. M. J. Am. Chem. Soc.
2012, 134, 17384. (d) Houghton, A. Y.; Hurmalainen, J.;
Mansikkamäki, A.; Piers, W.; Tuononen, H. M. T. Nat. Chem. 2014,
6, 983.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
(14) (a) Nöth, H. Z. Naturforsch. 1984, 39b, 1463. (b) Ishiyama,
T.; Murata, M.; Ahiko, T.; Miyaura, N. Org. Synth. 2000, 77, 176.
( 15 )
A
related compound, N,N’-bis(dimesitylboryl)-4,4’-
bipyridinylidene, has been reported. (a) Lichtblau, A.; Kaim, W.;
Schulz, A.; Stahl, T. J. Chem. Soc., Perkin Trans. 2 1992, 1497. (b)
Lichtblau, A.; Hausen, H.-D.; Schwarz, W.; Kaim, W. Inorg. Chem.
1993, 32, 73.
(16) The adducts 3c and 3d were relatively unstable under the
reaction conditions, thus the reaction at 110 °C resulted in significant
degrease of the yields because of product decomposition.
(17) For precedents of N,N’-diboryl-1,4-dihydropyrazines, see refs.
12 and 15.
(18) We separately found that the stoichiometric reaction of 1 with
2a was faster in cyclohexane than in benzene. Indeed, at 110 °C after
6 h, the reaction in cyclohexane provided 78% yield of product 3a,
while that in benzene gave 66% yield. This result may indicate that
improvement of catalyst efficiency by using cyclohexane as a solvent
can be attributed at least to the acceleration of the reductive addition
step.
(19) Although dearomatized 5 were air and moisture sensitive, they
were thermally stable and could be purified by distillation.
(20) There has been much interest in the chemistry of 1,4-
dihydropyrazines, including their synthetic utilities and structural
features as exemplified below. Applications in inorganic synthesis: (a)
Saito, T.; Nishiyama, H.; Tanahashi, H.; Kawakita, K.; Tsurugi, H.;
Mashima, K. J. Am. Chem. Soc. 2014, 136, 5161. Studies focused on
the antiaromatic character arising from their conjugated cyclic 8π-
electron structure: (b) Kaim, W. Angew. Chem. Int. Ed. 1981, 20, 599.
(c) Kaim, W. J. Am. Chem. Soc. 1983, 105, 707. (d) Lichtblau, A.;
Ehlend, A.; Hausen, H.-D.; Kaim, W. Chem. Ber. 1995, 128, 745. See
also ref. 15. Studies focused on their electron-rich ring systems: (e)
Kaim, W. Angew. Chem. Int. Ed. 1981, 20, 600. (f) Brook, D. J. R.;
Haltiwanger, R. C.; Koch, T. H. J. Am. Chem. Soc. 1991, 113, 5910.
(g) Brook, D. J. R.; Haltiwanger, R. C.; Koch, T. H. J. Am. Chem. Soc.
1992, 114, 6017. Studies on their key role in the structure of redox-
active biological molecules: (h) Goto, T.; Kishi, Y. Angew. Chem. Int.
Ed. 1968, 7, 407. (i) Walsh, C. Acc. Chem. Res. 1980, 13, 148.
(21) The parent quinoxaline underwent addition of 1 at 60 °C in the
absence of the bipyridine catalyst (see Supporting Information).
ACS Paragon Plus Environment