Highly Chemo-, Regio-, and Stereoselective Cobalt-Catalyzed Markovnikov Hydrosilylation of Alkynes

Article abstract of DOI:10.1002/anie.201605501

A highly chemo-, regio- and stereoselective cobalt-catalyzed Markovnikov hydrosilylation of alkynes was developed. Various functionalized groups, such as halides, free alcohols, free aniline, ketones, esters, amides, and nitriles are tolerated, which may lead to further applications and late-stage derivatizations. To date, this is the most efficient cobalt catalytic system (TOF=65 520 h^?1; TOF=turnover frequency) for hydrosilylation of alkynes. The Hiyama–Denmark cross-coupling reactions of vinylsilanes with aryl iodides underwent smoothly to afford 1,1-diarylethenes. A unique regioselectivity-controllable hydrosilylation/hydroboration reaction of alkynes was also described.

Full text of DOI:10.1002/anie.201605501

Angewandte
Communications
Chemie
International Edition: DOI: 10.1002/anie.201605501
German Edition: DOI: 10.1002/ange.201605501
Hydrosilylation of Alkynes
Highly Chemo-, Regio-, and Stereoselective Cobalt-Catalyzed
Markovnikov Hydrosilylation of Alkynes
Jun Guo and Zhan Lu*
Abstract: A highly chemo-, regio- and stereoselective cobalt-
catalyzed Markovnikov hydrosilylation of alkynes was devel-
oped. Various functionalized groups, such as halides, free
alcohols, free aniline, ketones, esters, amides, and nitriles are
tolerated, which may lead to further applications and late-stage
derivatizations. To date, this is the most efficient cobalt catalytic
system (TOF = 65520 hÀ1; TOF = turnover frequency) for
hydrosilylation of alkynes. The Hiyama–Denmark cross-
coupling reactions of vinylsilanes with aryl iodides underwent
smoothly to afford 1,1-diarylethenes. A unique regioselectivity-
controllable hydrosilylation/hydroboration reaction of alkynes
was also described.
of terminal alkynes.[14] Deng and co-workers demonstrated
that a three-coordinate carbene–phosphane cobalt complex
showed highly catalytic b-selectivity in the hydrosilylation of
terminal alkynes.[15] The use of cobalt complexes for promot-
ing the efficient, general and highly a-regioselective hydro-
silylation of alkynes has not been described previously. Here,
we developed a highly chemo-, regio-, and stereoselective
cobalt-catalyzed hydrosilylation of terminal and internal
alkynes to a-vinyl silanes (Scheme 1).
T
he development of efficient, selective, economic, and
environmentally benign catalysts[1] for valuable chemicals is
highly desirable and particularly beneficial for exploring new
transformations. Vinylsilanes are highly attractive intermedi-
ates because of versatile applications in organic synthesis and
materials science.[2] Hydrosilylation of alkynes with silanes is
one of the most straightforward and atom-economical
strategies.[3] However, only a few examples using noble
transition-metal catalysts, such as ruthenium,[4] have been
used for general Markovnikov-type hydrosilylation of
alkynes. Because of good tolerance to various functional
groups, as well as the lower costs and toxicity of cobalt
catalysts, rapid progress has been made in cobalt-catalyzed
reactions during the last two decades.[5] Recently, the research
groups of Chirik,[6] Hanson,[7] Holland,[8] Deng,[9] and
Huang[10] and our group[11] reported low-valent cobalt com-
plexes that efficiently catalyze hydrogenation, hydrosilyla-
tion, hydroboration, and isomerization of unsaturated
carbon–carbon double bonds. However, the cobalt-catalyzed
hydrosilylation of terminal alkynes is still challenging.[12]
Isobe and co-workers reported that a cobalt carbonyl
complex promoted the hydrosilylation reaction of function-
alized terminal alkynes with silanes to afford vinylsilanes,
however, with 1.2/1 to 6.7/1 regioselectivities.[13] Butenschçn
and co-workers found that the cyclopentadienylcobalt com-
plex with a pendant phosphane donor catalyzed the hydro-
silylation of internal alkynes with high syn-selectivity, how-
ever, no regioselectivity was observed in the hydrosilylation
Scheme 1. Cobalt complexes for catalytic hydrosilylation of terminal
alkynes
A simple phenylacetylene was chosen as a model sub-
strate and reacted with Ph2SiH2. The bench-stable oxazoline
iminopyridine (OIP) cobalt complex L1·CoCl2 was selected as
a precatalyst in which the OIP ligand could be easily
synthesized from substituted 2-bromopyridines and oxazo-
lines.[16] The reaction was carried out in the presence of
2 mol% cobalt precatalyst L1a·CoCl2 and 6 mol% NaBHEt3
as a reductant in a solution of tetrahydrofuran (THF) at room
temperature to afford a mixture of branched- and linear-
selective products in 18% yield with a ratio of 67:33 (see
entry 1 in Table 1). A significant increase in the yield as well
as in the regioselectivity was observed when a smaller benzyl
group was used on the oxazoline, which gave rise to vinyl-
silane in 83% yield with 87/13 regioselective ratio (rr;
entries 1–3). When the substitutent was further reduced in
size to a methyl group, the yield and regioselectivity slightly
decreased (entry 4). We were pleased to find that the
regioselectivities were improved to 94:6 using less steric
bulky 2,6-dimethyl or 2,4-dimethyl aniline-derived ligands
(entries 5 and 6). Using bromide or iodide as an anion instead
of chloride, a regioselectivity of upto 97:3 was observed
(entries 7 and 8). A variety of reductants, as well as various
solvents and silianes have also been investigated, but no
further improvement was observed (see the Supporting
Information). Control experiments were conducted and
showed cobalt complexes with well-defined ligands, such as
pyridine bisoxazoline (Pybox), bisiminopyridine (BIP), and
iminopyridine (IP), that promoted the reactions, however,
with slightly lower regioselectivities (entries 9–11).
[*] J. Guo, Prof. Z. Lu
Department of Chemistry, Zhejiang University
Hangzhou, Zhejiang 310058 (China)
E-mail: luzhan@zju.edu.cn
Homepage: http://mypage.zju.edu.cn/lu
Supporting information and the ORCID identification number(s) for
the author(s) of this article can be found under http://dx.doi.org/10.
1002/anie.201605501.
Angew. Chem. Int. Ed. 2016, 55, 1 – 5
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1
These are not the final page numbers!

Angewandte
Communications
Chemie
Table 1: Optimizations.[a]
underwent the reactions with Ph2SiH2 to afford the corre-
sponding hydrosilylation products (3a–n) in high yields and
excellent regioselectivities. For more broadly synthetic inter-
ests, various functionalized groups, such as halides, free
alcohols, free aniline, ketones, esters, amides, and nitriles
were tolerated. The reaction of 1k contaning an aldehyde
moiety were carried out to afford 3k in a slightly lower yield
with 93/7 rr. 2-Naphthyl (1o), 1-naphthyl (1p), 2-thienyl (1q),
3-pyridyl (1r) alkynes could be delivered to a-silyl alkenes in
80–89% yields with 93/7 to 98/2 rr. The reaction of alkyl-
substituted terminal alkynes[18] and silylalkynes[19] underwent
smoothly with a slightly lower regioselectivity. A variety of
gram-scale reactions using 0.4 mol% of L1 f·CoBr2 were
carried out and the crude products were purified by recrys-
tallization to afford the corresponding vinyl silylanes in 80–
89% yields at gram scale (Table 3).
Entry
[Co]
Yield[b] [%] (b/l)
1
2
3
4
5
6
7
8
L1a·CoCl2
L1b·CoCl2
L1c·CoCl2
L1d·CoCl2
L1e·CoCl2
L1 f·CoCl2
L1 f·CoBr2
L1 f·CoI2
18 (67/33)
38 (71/29)
83 (87/13)
77(85/15)
77 (93/7)
88 (94/6)
90 (97/3)
88 (96/4)
79 (86/14)
61 (69/31)
87 (78/22)
Table 3: Gram-scale reactions.[a]
9
10
11
L2·CoBr2
L3·CoBr2
L4·CoBr2
[a] Phenylacetylene (1 mmol), Ph2SiH2 (1 mmol), cobalt complex
(2 mol%), NaBHEt3 (6 mol %) in THF (2 mL). [b] Yield and regiose-
lective ratio were determined by 1H NMR using TMSPh as an internal
standard.
[a] 1 (5 mmol), Ph2SiH2 (5 mmol), L1 f·CoBr2 (0.4 mol%), NaBHEt3
(1.5 mol %) in THF (2 mL), isolated yield of 3. [b] 1.0 mol% of L1 f·CoBr2
was used.
The scope of this catalytic system turned out to be broad
(Table 2). Under the optimal conditions using L1 f·CoBr2
complex,[17] a variety of alkynes bearing electron-donating
or electron-withdrawing substituents on the phenyl ring
Internal alkynes could also be hydrosilylated under this
cobalt-catalyzed conditions (Table 4). The hydrosilylations of
symmetric dialkyl alkynes (5a,b), as well as diaryl alkyne
(5c), provided only syn-addition products with high stereo-
selectivity. The unsymmestric internal alkynes, such as aryl
alkyl alkynes (5d–h), were suitable for this method to
produce 1-aryl-1-silyl-2-alkyl alkenes in 79–90% yield and
85:15 to 91:9 rr. The aryl heteroaryl alkyne (5i) and alkyl alkyl
Table 2: Scope for hydrosilylation of terminal alkynes.[a]
Table 4: Hydrosilylation of internal alkynes.[a]
[a] 1 (1 mmol), Ph2SiH2 (1 mmol), L1 f·CoBr2 (2 mol%), NaBHEt3 (6 mol
%) in THF (2 mL), isolated yield and ratio of b/l. [b] Reacted for
30 minutes.
[a] 5 (1 mmol), Ph2SiH2 (1 mmol), L1 f·CoBr2 (2 mol%), NaBHEt3 (6 mol
%) in THF (2 mL), isolated yield and ratio of 6/7.
2
www.angewandte.org
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2016, 55, 1 – 5
These are not the final page numbers!

Angewandte
Communications
Chemie
alkyne (5j) could be converted to hydrosilylation products 6i
and 6j in 68% yield with 90/10 rr and 89% yield with > 99/
1 rr, respectively.
The reaction could complete even in 5 s using 1 mol% of
catalyst to afford silylation products in 91% yield with 93/7 rr
[Eq. (1)] in which the turnover frequency was upto 65520 hÀ1
.
To date, this is the most efficient cobalt catalytic system for
hydrosilylation of alkynes. 4’-Vinylphenylacetylene 1u could
be converted to the alkyne hydrosilylation product 3u in 55%
yield with > 95/5 rr without any alkene hydrosilylation
product [Eq. (2)] which suggested that the catalytic system
could differentiate between terminal alkyne and terminal
alkene which used to be active in cobalt-catalyzed hydro-
silylation reactions.[11,20] Based on the above experimental
results and those in previously reported literatures, a Chalk–
Harrod mechanism[20b] for hydrosilylation of alkenes was
proposed, however, we did not have any evidence and further
mechanistic studies should be carried out [Eqs. (1) and 2].
Scheme 3. Double-Markovnikov hydrosilylation/hydroboration of
alkynes. [a] 2 mol% of the catalyst were used.
obtain[24] (Scheme 3). The solvent effect might be the major
effect for the switch in reagioselectivity (see the Supporting
Information). Various functional groups, such as esters,
amides, naphthyl and thienyl, were tolerated. Although
poor enantioselectivities (around 10% ee) were observed,
the same cobalt complex promoted two different reactions in
one pot.
The Hiyama–Denmark coupling reactions[25] of 3a with
aryl iodides (see Scheme 4) was carried out smoothly to
afford the 1,1-diarylethene 10a and 10b in 80% and 82%
yield, respectively.
Hydroboration of alkenes is one of the most useful
methods to access alkylboronic acid derivatives which are
widely used in modern organic synthesis.[21] Only few
examples on hydroboration of vinylsilanes were reported,[22]
however, enantioselective reactions have not been previously
described thus far. To explore the broader utility of a-silyl
alkenes, the cobalt-catalyzed asymmetric anti-Markovnikov
hydroboration[10a,11a] of a-silyl alkenes with pinacol borane
(HBPin) using L1a·CoCl2 as a precatalyst and NaBHEt3 as
a reductant in a solution of toluene underwent smoothly to
exclusively afford 8 in 76–82% yields and 80–85% ee
(Scheme 2).
Scheme 4. Hiyama–Denmark coupling reactions of 3a.
In summary, we developed a highly chemo-, regio-, and
stereoselective cobalt-catalyzed hydrosilylation of alkynes
with silanes to produce a-vinylsilanes. Various functionalized
groups, such as halides, free alcohols, free aniline, ketones,
esters, amides, and nitriles, are tolerated to increase the
possibility for further applications and late-stage derivatiza-
tions. To date, this is the most efficient cobalt catalytic system
(TOF = 65520 hÀ1; TOF = turnover frequency) for the hydro-
silylation of alkynes. The direct asymmetric hydroboration of
a-vinylsilanes exclusively afforded anti-Markovnikov prod-
ucts. The one-pot reaction combined with hydrosilylation and
hydroboration provided double-Markovnikov addition prod-
ucts. It is the first time that regioselectivity-controllable
hydrosilylation/hydroboration of alkynes were observed. The
Hiyama–Denmark cross-coupling reaction of vinylsilanes
with aryl iodides underwent smoothly to afford 1,1-diaryl-
ethenes. Mechanistic studies will be conducted in our
laboratory.
Scheme 2. Asymmetric anti-Markovnikov hydroboration of a-silyl
alkenes.
To our surprise, the combination of hydrosilylation and
hydroboration reactions of alkynes in THF in one pot did
provide double-Markovnikov hydrosilylation/hydrobora-
tion[23] products 9 in 39–78% yields which were difficult to
Angew. Chem. Int. Ed. 2016, 55, 1 – 5
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
3
These are not the final page numbers!

Angewandte
Communications
Chemie
[10] a) L. Zhang, Z. Zuo, X. Wan, Z. Huang, J. Am. Chem. Soc. 2014,
136, 15501; b) X. Du, Y. Zhang, D. Peng, Z. Huang, Angew.
Chem. Int. Ed. 2016, 55, 6671; Angew. Chem. 2016, 128, 6783.
[11] a) J. Chen, T. Xi, X. Ren, J. Guo, B. Cheng, Z. Lu, Org. Chem.
Front. 2014, 1, 1306; b) J. Chen, C. Chen, C. Ji, Z. Lu, Org. Lett.
2016, 18, 1594.
Acknowledgements
Financial support was provided by the National 973 Program
(2015CB856600), NSFC (grant number21472162), and the
“Thousand Youth Talents Plan”.
[12] J. Sun, L. Deng, ACS Catal. 2016, 6, 290.
[13] a) M. Isobe, R. Nishizawa, T. Nishikawa, K. Yoza, Tetrahedron
Lett. 1999, 40, 6927; b) S. Tojo, M. Isobe, Tetrahedron Lett. 2005,
46, 381; c) K.-H. Huang, M. Isobe, Eur. J. Org. Chem. 2014, 4733;
d) T. Konno, K. Taku, S. Yamada, K. Moriyasu, T. Ishihara, Org.
Biomol. Chem. 2009, 7, 1167.
Keywords: alkynes · cobalt catalysis · homogeneous catalysis ·
hydroboration · hydrosilylation
[14] L. Yong, K. Kirleis, H. Butenschçn, Adv. Synth. Catal. 2006, 348,
833.
[15] Z. Mo, J. Xiao, Y. Gao, L. Deng, J. Am. Chem. Soc. 2014, 136,
17414.
[16] a) J. Chen, T. Xi, Z. Lu, Org. Lett. 2014, 16, 6452; b) T. Xi, Y.
Mei, Z. Lu, Org. Lett. 2015, 17, 5939.
[17] CCDC 1435433 contains the supplementary crystallographic
data for this paper. These data can be obtained free of charge
from The Cambridge Crystallographic Data Centre via www.
ccdc.cam.ac.uk/data_request/cif.
[18] For a selected example on highly selective hydrosilylation of
alkyl alkynes, see: P. Wang, X.-L. Yeo, T.-P. Loh, J. Am. Chem.
Soc. 2011, 133, 1254.
[19] For a selected example on highly selective hydrosilylation of silyl
alkynes, see: S. Ding, L.-J. Song, L. W. Chung, X. Zhang, J. Sun,
Y.-D. Wu, J. Am. Chem. Soc. 2013, 135, 13835.
[20] For selected examples on cobalt-catalyzed hydrosilylation of
alkenes, see: a) J. F. Harrod, A. J. Chalk, J. Am. Chem. Soc. 1965,
87, 1133; b) A. J. Chalk, J. F. Harrod, J. Am. Chem. Soc. 1967, 89,
1640; c) A. J. Chalk, J. Organomet. Chem. 1970, 21, 207; d) F.
Seitz, M. S. Wrighton, Angew. Chem. Int. Ed. Engl. 1988, 27, 289;
Angew. Chem. 1988, 100, 281; e) M. Brookhart, B. E. Grant, J.
Am. Chem. Soc. 1993, 115, 2151.
[21] For some selected reviews, see: a) H. C. Brown, Organic Syn-
thesis via Boranes, Wiley, New York, 1975; b) H. C. Brown, B.
Singaram, Pure Appl. Chem. 1987, 59, 879; c) R. Jana, T. P.
Pathak, M. S. Sigman, Chem. Rev. 2011, 111, 1417; d) H. K.
Scott, V. K. Aggarwal, Chem. Eur. J. 2011, 17, 13124; For some
selected examples, see: e) J. L. Stymiest, V. Bagutski, R. M.
French, V. K. Aggarwal, Nature 2008, 456, 778; f) V. Bagutski,
R. M. French, V. K. Aggarwal, Angew. Chem. Int. Ed. 2010, 49,
5142; Angew. Chem. 2010, 122, 5268; g) A. Bonet, M. Oda-
chowski, D. Leonori, S. Essafi, V. K. Aggarwal, Nat. Chem. 2014,
6, 584.
[22] D. J. Parks, W. E. Piers, Tetrahedron 1998, 54, 15469.
[23] For a review on catalytic regioselective functionalization of
alkenes, see: M. Beller, J. Seayad, A. Tillack, H. Jiao, Angew.
Chem. Int. Ed. 2004, 43, 3368; Angew. Chem. 2004, 116, 3448.
[24] V. K. Aggarwal, M. Binanzer, M. C. D. Ceglie, M. Gallanti, B. W.
Glasspoole, S. J. F. Kendrick, R. P. Sonawane, A. Vꢀzquez-
Romero, M. P. Webster, Org. Lett. 2011, 13, 1490.
[25] a) Y. Hatanaka, S. Fukushima, T. Hiyama, Heterocycles 1990, 30,
303; b) S. E. Denmark, Z. Wang, J. Organomet. Chem. 2001, 624,
372; c) S. E. Denmark, J. H.-C. Liu, J. Am. Chem. Soc. 2007, 129,
3737.
[1] Catalysis without Precious Metals (Ed.: R. M. Bullock), Wiley-
VCH, Weinheim, 2010.
[2] a) T. H. Chan, I. Fleming, Synthesis 1979, 761; b) T. A. Blumen-
kopf, L. E. Overman, Chem. Rev. 1986, 86, 857; c) E. Langkopf,
D. Schinzer, Chem. Rev. 1995, 95, 1375; d) I. Fleming, A.
Barbero, D. Walter, Chem. Rev. 1997, 97, 2063.
[3] a) T. Hiyama, T. Kusumoto in Comprehensive Organic Synthesis,
Vol. 8 (Eds.: B. M. Trost, I. Fleming), Pergamon, Oxford, 1991,
p. 763; b) H. Brunner, Angew. Chem. Int. Ed. 2004, 43, 2749;
Angew. Chem. 2004, 116, 2805; c) Hydrosilylation: A Compre-
hensive Review on Recent Advances (Ed.: B. Marciniec),
Springer, Amsterdam, 2009.
[4] a) B. M. Trost, Z. T. Ball, J. Am. Chem. Soc. 2001, 123, 12726;
b) B. M. Trost, Z. T. Ball, J. Am. Chem. Soc. 2005, 127, 17644;
c) Y. Na, S. Chang, Org. Lett. 2000, 2, 1887; d) Y. Kawanami, Y.
Sonoda, T. Mori, K. Yamamoto, Org. Lett. 2002, 4, 2825; e) C.
Menozzi, P. I. Dalko, J. Cossy, J. Org. Chem. 2005, 70, 10717;
f) H. F. Sore, D. T. Blackwell, S. J. F. MacDonald, D. R. Spring,
Org. Lett. 2010, 12, 2806.
[5] For selected reviews on cobalt chemistry: a) F. Hebrard, P.
Kalck, Chem. Rev. 2009, 109, 4272; b) K. Gao, N. Yoshikai, Acc.
Chem. Res. 2014, 47, 1208; c) H. Pellissier, H. Clavier, Chem.
Rev. 2014, 114, 2775; d) P. Gandeepan, C. Cheng, Acc. Chem.
Res. 2015, 48, 1194; e) N. Kaeffer, M. Chavarot-Kerlidou, V.
Artero, Acc. Chem. Res. 2015, 48, 1286; f) P. J. Chirik, Acc.
Chem. Res. 2015, 48, 1687; g) Y. Li, S. Yu, W. Shen, J. Gao, Acc.
Chem. Res. 2015, 48, 2587.
[6] a) S. Monfette, Z. R. Turner, S. P. Semproni, P. J. Chirik, J. Am.
Chem. Soc. 2012, 134, 4561; b) M. R. Friedfeld, M. Shevlin, J. M.
Hoyt, S. W. Krska, M. T. Tudge, P. J. Chirik, Science 2013, 342,
1076; c) J. V. Obligacion, P. J. Chirik, J. Am. Chem. Soc. 2013,
135, 19107; d) M. R. Friedfeld, G. W. Margulieux, B. A. Schae-
fer, P. J. Chirik, J. Am. Chem. Soc. 2014, 136, 13178; e) C. C. H.
Atienza, T. Diao, K. J. Weller, S. A. Nye, K. M. Lewis, J. G. P.
Delis, J. L. Boyer, A. K. Roy, P. J. Chirik, J. Am. Chem. Soc. 2014,
136, 12108; f) J. V. Obligacion, J. M. Neely, A. N. Yazdani, I.
Pappas, P. J. Chirik, J. Am. Chem. Soc. 2015, 137, 5855; g) M. R.
Friedfeld, M. Shevlin, G. W. Margulieux, L.-C. Campeau, P. J.
Chirik, J. Am. Chem. Soc. 2016, 138, 3314.
[7] a) G. Zhang, B. L. Scott, S. K. Hanson, Angew. Chem. Int. Ed.
2012, 51, 12102; Angew. Chem. 2012, 124, 12268; b) G. Zhang,
K. V. Vasudevan, B. L. Scott, S. K. Hanson, J. Am. Chem. Soc.
2013, 135, 8668.
[8] a) C. Chen, T. R. Dugan, W. W. Brennessel, D. J. Weix, P. L.
Holland, J. Am. Chem. Soc. 2014, 136, 945; b) C. Chen, M. B.
Hecht, A. Kavara, W. W. Brennessel, B. Q. Mercado, D. J. Weix,
P. L. Holland, J. Am. Chem. Soc. 2015, 137, 13244.
[9] Z. Mo, Y. Liu, L. Deng, Angew. Chem. Int. Ed. 2013, 52, 10845;
Angew. Chem. 2013, 125, 11045.
Received: June 6, 2016
Published online: && &&, &&&&
4
www.angewandte.org
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2016, 55, 1 – 5
These are not the final page numbers!

Angewandte
Communications
Chemie
Communications
Hydrosilylation of Alkynes
J. Guo, Z. Lu*
&&&& — &&&&
Highly Chemo-, Regio-, and
Stereoselective Cobalt-Catalyzed
Markovnikov Hydrosilylation of Alkynes
Cobalt catalysis: A highly chemo-, regio-
and stereoselective cobalt-catalyzed
hydrosilylation reaction of alkynes with
silanes was developed (see picture;
HBPin=pinacol borane; TOF=turnover
frequency). The reaction tolerates various
functionalized groups, which may lead to
further applications and late-stage deri-
vatizations.
Angew. Chem. Int. Ed. 2016, 55, 1 – 5
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
5
These are not the final page numbers!