Deprotonation and addition reactions of frustrated Lewis pairs with alkynes

Article abstract of DOI:10.1021/om1009044

Deprotonation of terminal alkynes is effected by the treatment with tBu₃P and B(C₆F₅)₃ to give [tBu ₃PH][PhCCB(C₆F₅)₃] (1a) and [tBu₃PH][RCCB(C₆F

Full text of DOI:10.1021/om1009044

6594 Organometallics 2010, 29, 6594–6607
DOI: 10.1021/om1009044
Deprotonation and Addition Reactions of Frustrated Lewis Pairs with
Alkynes
Meghan A. Dureen, Christopher C. Brown, and Douglas W. Stephan*
Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario,
Canada, M5S 3H6
Received September 20, 2010
Deprotonation of terminal alkynes is effected by the treatment with tBu3P and B(C6F5)3 to give
[tBu3PH][PhCCB(C6F5)3] (1a) and [tBu3PH][RCCB(C6F5)3] (R = nBu 2, tBu 3, Me3Si 4, and
CpFe(C5H4) 5). In a similar fashion, FLP deprotonation of 1,4-diethynylbenzene was employed to
prepare the salt [tBu3PH]2[(C6F5)3BCC(C6H4)CCB(C6F5)3] (6). As well, use of differing Lewis acids
afforded the species [tBu3PH][PhCCEAr3] (EAr3 = Al(C6F5)3 7, PhB(C6F5)2 8, BPh3 9). The
corresponding reaction of Me3SiCCSiMe3 afforded [tBu3PSiMe3][Me3SiCCB(C6F5)3] (10). For less
basic phosphines, phosphine/borane addition reactions were observed with alkynes. Thus the species
E-R3P(Ph)CdC(H)B(C6F5)3 (R=o-tol 11, Ph 12) were prepared. In the latter case, Ph3P B(C6F5)3
3
wasemployed. Similarly,E-Ph3P(CpFe(C5H4))CdC(H)B(C6F5)3 (13), E-Ph3P(Ph)CdC(Me)B(C6F5)3
(14), E-R2PH(Ph)CdC(H)B(C6F5)3 (R = Ph 15, C6H2Me3 16), and E-(C6H2tBu3)PH2(Ph)Cd
C(H)B(C6F5)3 (17) were prepared. Again, variation in the Lewis acid afforded E-Ph3P(Ph)Cd
C(H)EAr3 (EAr3 = PhB(C6F5)2 18, Al(C6F5)3 19), E-Ph3P(nBu)CdC(H)Al(C6F5)3 (20), and E-(o-
tol)3P(Ph)CdC(H)Al(C6F5)3 (21). The macrocyclic [(H)CdC(Ph)Mes2PC6F4B(C6F5)2]2 (22) was
prepared from the analogous alkyne addition to Mes2PC6F4B(C6F5)2, while E-Ph2PCH2CH2PPh2-
(Ph)CdC(H)B(C6F5)3 (23) and E-(CH2PPh2(Ph)CdC(H)B(C6F5)3)2 (24) were derived from the
reactions of Ph2PCH2CH2PPh2. The related addition reaction involving 1,4-diethynylbenzene gave
E-HCtCC6H4C(PPh3)dC(H)B(C6F5)3 (25), while subsequent reaction with tBu3P and B(C6F5)3
yielded the unusual salt/zwitterion [tBu3PH][(C6F5)3BCCtC6H4C(PPh3)dC(H)-B(C6F5)3] (26).
Reaction of PhCH2NMe2 with PhCCH and B(C6F5)3 gave give a 84:16 mixture of
[PhCH2NMe2H][PhCCB(C6F5)3] (27a) and PhCH2NMe2(Ph)CdC(H)B(C6F5)3 (27b), while imines
were used to prepare [(tBu)HNdCHPh][PhCCB(C6F5)3] (28) and [(tBu)HNdCPh2][PhCCB(C6F5)3]
(29). The corresponding reaction of tBuNCNtBu, B(C6F5)3, and two equivalents of PhCCH led to
the unusual product [tBuNCN(H)C(Ph)dC(H)tBu][PhCCB(C6F5)3] (30). Finally, non-pnictogen
Lewis bases were explored. The reaction of the N-heterocyclic carbene ItBu with B(C6F5)3 and
PhCCH was shown to yield the deprotonation product [ItBuH][PhCCB(C6F5)3] (31), while the
sulfides R2S gave E-R2S(Ph)CdC(H)B(C6F5)3 (R = Me 32, PhCH2 33). The formation of these latter
sulfide zwitterions was demonstrated to be reversible.
Introduction
organic manipulation of alkynes, whether via vinyl boranes,
alkynyl boranes, alkynyl borates, or a myriad of other
synthons, is also well established.5-7 Of particular relevance
to the present work is the utility of B(C6F5)3 in mediating the
catalytic hydrostannation8 or hydrogermylation9 of alkynes
as well as the intramolecular addition of silyl enol ethers to
alkynes.10 In related reactivity Erker and co-workers have
reported the cyclization of dialkynylsilanes employing
Alkyne activation by transition metals is an important
reaction in the synthetic toolbox of organic chemists.1 Me-
talations of terminal alkynes provide useful synthons, while
transition metal-catalyzed reactions allow a variety of
C-C coupling reactions including oxidative dimerizations,2
alkyne-arene coupling reactions,3 and alkynylations of
aldehydes.4 Similarly, the utility of borane reagents in the
(5) Brown, H. C. Organic Synthesis via Boranes; John Wiley & Sons:
New York, 1975.
(6) Pelter, A.; Smith, K.; Brown, H. C. Borane Reagents; Academic
Press Limited: London, 1988.
(7) Mikhailov, B. M.; Bubnov, Y. N. Organoboron Compounds in
Organic Synthesis; Harwood Academic: New York, 1984.
(8) Gevorgyan, V.; Liu, J.-X.; Yamamoto, Y. Chem. Commun. 1998,
37–38.
(9) Schwier, T.; Gevorgyan, V. Org. Lett. 2005, 7, 5191–5194.
(10) Imamura, K.-I.; Yoshikawa, E.; Gevorgyan, V.; Sudo, T.; Asao,
N.; Yamamoto, Y. Can. J. Chem. 2001, 79, 1624–1631.
*To whom correspondence should be addressed. E-mail: dstephan@
chem.utoronto.ca.
(1) Parrodi, C. A. d.; Walsh, P. J. Angew. Chem., Int. Ed. 2009, 48,
4679–4682.
(2) Siemsen, P.; Livingston, R. C.; Diederich, F. Angew. Chem., Int.
Ed. 2000, 39, 2632.
(3) Sonogashira, K. Palladium-catalyzed Alkynylations. In Hand-
book of Organopalladium Chemistry for Organic Synthesis; Negishi, E.-i.,
Ed.; John Wiley & Sons: New York, 2002.
(4) Boyall, D.; Frantz, D. E.; Carreira, E. M. Org. Lett. 2002, 4, 2605.
r
pubs.acs.org/Organometallics
Published on Web 11/08/2010
2010 American Chemical Society

Article
Organometallics, Vol. 29, No. 23, 2010 6595
Scheme 1. Reactions of B(C6F5)3 and Alkynes
were initially shown to effect the heterolytic activation of
H2 and effect metal-free catalytic hydrogenations.22,2326-29
FLPs have also been shown to react with a variety of other
small molecules including THF,30,31 catechol borane,32
terminal olefins,33 dienes,34 CO2,35,36 N2O,37,38 and CO.39
We have also previously communicated the reactivity of
terminal alkynes with phosphine/Lewis acid combinations.
In these cases, two courses of reactions were observed, either
deprotonation of the alkyne derivatives to give phospho-
nium alkynyl-borates or addition reactions affording zwit-
terionic, alkenyl-phosphonium borate salts. In the latter
case, analogous reactivity has been exploited by Yamaguchi
and co-workers40 to effect intramolecular addition of phos-
phines and boranes, affording interesting electronic materials
(Scheme 1). Subsequently, Berke and co-workers described
the related reactions of the FLP system with acetylene and
other alkynes41 and also identified the products of reaction
of B(C6F5)3 and alkyne alone (Scheme 1). In this paper, we
expand the scope and explore the features of this FLP
reactivity with alkynes developing a broader sense of how
this reactivity applies to a range of terminal alkynes and
nucleophiles including phosphines, nitrogen bases, carbenes,
and thioethers.
B(C6F5)3 (Scheme 1); however this reaction is believed to
proceed by abstraction of an acetylide from the Si center
rather than electrophilic attack of the borane on the π
bond.11 This latter reaction is thought to be analogous to
the reactivity of BEt3 with dialkyl stannanes and silanes,12
and similar reactivity has also led to the synthesis of a variety
of interesting group IV zwitterions from the reaction of metal
alkyne complexes with B(C6F5)3.13-16
In our own chemistry we have been exploring the activa-
tion of a variety of small molecules employing combinations
of electrophilic and nucleophilic reagents that act simulta-
neously or sequentially on a substrate by exploiting steric
congestion to preclude the direct reaction of the electrophile
and nucleophile. Remarkably, such frustrated Lewis pairs
(FLPs)17-19 comprised of a sterically encumbered phosphine,20,21
imine,22,23 or carbene24,25 and an electron-deficient borane
Experimental Section
General Considerations. All manipulations were carried out
under an atmosphere of dry, O2-free N2 employing a Vacuum
Atmospheres glovebox and a Schlenk-type vacuum line. Solvents
were purified with a Grubbs-type column system manufactured
by Innovative Technology and dispensed into thick-walled
Schlenk glass flasks equipped with Teflon-valve stopcocks
(pentane, toluene, CH2Cl2) or were dried over the appropriate
agents and distilled into the same kind of storage flasks
(C6H5Br). All solvents were thoroughly degassed after purifica-
tion (repeated freeze-pump-thaw cycles). Deuterated solvents
were dried over the appropriate agents, vacuum-transferred into
storage flasks with Teflon stopcocks, and degassed accordingly
(C6D5Br, CD2Cl2). Toluene and pentane were stored over
€
(11) Dierker, G.; Ugolotti, J.; Kehr, G.; Frohlich, R.; Erker, G. Adv.
Synth. Catal. 2009, 351, 1080–1088.
(12) Killian, L.; Wrackmeyer, B. J. Organomet. Chem. 1977, 132,
213–221.
potassium mirrors, while bromobenzene and CH2Cl2 were
stored over 4 A molecular sieves. H, 11B, 13C, 19F, and 31P
˚
NMR spectra were recorded at 25 °C on Varian 300 and 400
MHz and Bruker 400 MHz spectrometers. Chemical shifts are
1
€
(13) Erker, G.; Ahlers, W.; Frohlich, R. J. Am. Chem. Soc. 1995, 117,
5853–5854.
(14) Ahlers, W.; Erker, G.; Frohlich, R.; Peuchert, U. J. Organomet.
€
Chem. 1999, 578, 115–124.
(15) Arndt, P.; Baumann, W.; Spannenberg, A.; Rosenthal, U.;
Burlakov, V. V.; Shur, V. B. Angew. Chem., Int. Ed. 2003, 42, 1414–1418.
(16) Burlakov, V. V.; Arndt, P.; Baumann, W.; Spannenberg, A.;
Rosenthal, U. Organometallics 2004, 23, 5188–5192.
(17) Stephan, D. W. Org. Biomol. Chem. 2008, 6, 1535.
(18) Kenward, A. L.; Piers, W. E. Angew. Chem., Int. Ed. 2008, 47,
38–41.
(29) Sumerin, V.; Schulz, F.; Nieger, M.; Leskela, M.; T., R.; Rieger,
B. Angew. Chem., Int. Ed. 2008, 47, 6001.
(30) Welch, G. C.; Cabrera, L.; Chase, P. A.; Hollink, E.; Masuda,
J. D.; Wei, P.; Stephan, D. W. Dalton Trans. 2007, 3407.
(31) Welch, G. C.; Prieto, R.; Dureen, M. A.; Lough, A. J.; Labeodan,
€
€
O. A.; Holtrichter-Rossmann, T.; Stephan, D. W. Dalton Trans. 2009,
1559.
(19) Welch, G. C.; Juan, R. R. S.; Masuda, J. D.; Stephan, D. W.
Science 2006, 314, 1124.
(20) Welch, G. C.; Stephan, D. W. J. Am. Chem. Soc. 2007, 129, 1880.
(21) Ullrich, M.; Lough, A. J.; Stephan, D. W. J. Am. Chem. Soc.
2009, 131, 52.
(32) Dureen, M. A.; Stephan, D. W. Chem. Commun. 2008, 4303.
(33) McCahill, J. S. J.; Welch, G. C.; Stephan, D. W. Angew. Chem.,
Int. Ed. 2007, 46, 4968.
(34) Ullrich, M.; Seto, K. S.-H.; Lough, A. J.; Stephan, D. W. Chem.
Commun. 2009, 2335–2337.
(22) Chase, P. A.; Jurca, T.; Stephan, D. W. Chem. Commun. 2008,
1701.
(23) Chase, P. A.; Welch, G. C.; Jurca, T.; Stephan, D. W. Angew.
(35) Menard, G.; Stephan, D. W. J. Am. Chem. Soc. 2010, 132, 1796–
1797.
(36) Momming, C. M.; Kehr, G.; Wibbeling, B.; Frohlich, R.;
Schirmer, B.; Grimme, S.; Erker, G. Angew. Chem., Int. Ed. 2010, 49,
2414–2417.
(37) Neu, R. C.; Otten, E.; Lough, A.; Stephan, D. W. Chem. Sci.
2010, DOI: 10.1039/C0SC00398K.
€
€
Chem., Int. Ed. 2007, 49, 8050.
(24) Chase, P. A.; Stephan, D. W. Angew. Chem., Int. Ed. 2008, 47,
7433.
(25) Holschumacher, D.; Bannenberg, T.; Hrib, C. G.; Jones, P. G.;
Tamm, M. Angew. Chem., Int. Ed. 2008, 47, 7428.
(26) Spies, P.; Erker, G.; Kehr, G.; Bergander, K.; Frohlich, R.;
(38) Otten, E.; Neu, R. C.; Stephan, D. W. J. Am. Chem. Soc. 2009,
131, 9918–9919.
€
Grimme, S.; Stephan, D. W. Chem. Commun. 2007, 5072.
(27) Spies, P.; Schewendemann, S.; Lange, S.; Kehr, G.; Frohlich, R.;
Erker, G. Angew. Chem., Int. Ed. 2008, 47, 7543.
(28) Sumerin, V.; Schulz, F.; Atsumi, M.; Wang, C.; Nieger, M.;
(39) Dureen, M. A.; Stephan, D. W. J. Am. Chem. Soc. 2010, DOI:
10.1021/ja1064153.
(40) Fukazawa, A.; Yamada, H.; Yamaguchi, S. Angew. Chem., Int.
Ed. 2008, 47, 5582.
(41) Jiang, C.; Blacque, O.; Berke, H. Organometallics 2009, 29, 125–
133.
€
€
Leskela, M.; Repo, T.; Pyykko, P.; Rieger, B. J. Am. Chem. Soc. 2008,
130, 14117.

6596 Organometallics, Vol. 29, No. 23, 2010
Dureen et al.
given relative to SiMe4 and referenced to the residual solvent
signal (1H, 13C) or relative to an external standard (11B:
4.48. X-ray quality crystals were grown by slow cooling of a
solution in chlorobenzene.
3: white solid, 81 mg, 52%. H NMR (CD2Cl2): 5.0 (d, 1H,
1
Et2O BF3; 19F: CFCl3; 31P: 85% H3PO4). In some instances,
3
signal and/or coupling assignment was derived from two-dimen-
sional NMR experiments. Chemical shifts (δ) are reported in
ppm, and coupling constants (J) as scalar values in Hz. Com-
bustion analyses were performed in-house employing a Perkin-
Elmer CHN analyzer. Tris(pentafluorophenyl)borane was gen-
erously donated by NOVA Chemicals Corporation; tBu3P was
purchased from Strem Chemicals; all other reagents were pur-
chased from Aldrich. Phenylacetylene was vacuum transferred
from CaCl2 and stored at -35 °C in the glovebox. Liquids were
1JH-P=430 Hz, tBu3PH), 1.6 (d, 27H, 3JH-P=16 Hz, tBu3PH),
1.1 (s, 9H, CCMe3). 11B NMR (CD2Cl2): -21.0. 13C{1H} NMR
(CD2Cl2), partial: 148.6 (dm, JC-F =240 Hz, o-C6F5), 138.2
1
1
(dm, JC-F=238 Hz, p-C6F5), 136.8 (dm, 1JC-F=240 Hz, m-
C6F5), 37.9 (d, 1JC-F=28 Hz, PCMe3), 31.6 (s, CCMe3), 30.2 (s,
PCMe3), 28.06 (s, CCMe3). 19F NMR (CD2Cl2): -132.4 (d, 6F,
3JF-F=24 Hz, o-C6F5), -164.5 (t, 3F, 3JF-F=25 Hz, p-C6F5), -
167.7 (t, 3F, 3JF-F=21 Hz, m-C6F5). 31P{1H} NMR (CD2Cl2):
61.7. Anal. Calcd for C36H37BF15P (796.453): C, 54.29; H, 4.68.
Found: C, 54.18; H, 4.91.
stored over 4 A molecular sieves. (PhMe) Al(C6F5)3,42 Mes2PH,43
˚
3
PhB(C6F5)2,44 Mes2PC6F4B(C6F5)2,45 Ph2CdNtBu,46 and Ph3P
4: white solid, 100 mg, 63%. 1H NMR (C6D5Br): 4.0 (d, 1H,
1JH-P=430 Hz, tBu3PH), 0.8 (d, 27H, 3JH-P=16 Hz, tBu3PH),
0.0 (s, 9H, SiMe3). 11B NMR (CD2Cl2): -20.8. 13C{1H} NMR
3
B(C6F5)347-49 were prepared following literature methods.
Synthesis of [tBu3PH][RCCB(C6F5)3] (R=Ph (1a), C4H9 (2),
tBu (3), Me3Si (4), and CpFe(C5H4) (5)), [tBu3PH]2[1,4-C6H4-
(CCB(C6F5)3)2] (6), and [tBu3PH][PhCCEAr3] (EAr3 = Al-
(C6F5)3 (7), BPh(C6F5)2 (8), BPh3 (9)). These compounds were
prepared in a similar fashion, and thus only one preparation is
detailed. A solution of PhCtCH (75 mg, 1.5 mmol) and tBu3P
(303 mg, 1.5 mmol) in toluene (10 mL) was cooled to -35 °C, at
which point B(C6F5)3 (767 mg, 1.5 mmol) was added in one
portion, and the solution was shaken, not stirred, until all of the
borane had dissolved and a yellowish oil separated from the
toluene layer. This toluene layer was decanted and the oil dried
under reduced pressure to afford a yellowish solid. Recrystalli-
zation from PhCl (2 mL) afforded a colorless, crystalline solid
(805 mg, 75%), and layering of the supernatant PhCl with
pentane (3 mL) afforded an additional 75 mg of product for
an overall yield of 82%.
1
(CD2Cl2), partial: 148.8 (dm, JC-F =245 Hz, o-C6F5), 138.9
1
(dm, JC-F=236 Hz, p-C6F5), 137.1 (dm, 1JC-F=236 Hz, m-
C6F5), 38.3 (d, 1JC-P=27 Hz, PCMe3), 30.6 (s, PCMe3), 0.9 (s,
SiMe3). 19F NMR (C6D5Br): -130.4 (d, 6F, 3JF-F=23 Hz, o-
3
C6F5), -162.9 (t, 3F, JF-F =21 Hz, p-C6F5), -166.3 (t, 3F,
3JF-F=21 Hz, m-C6F5). 31P{1H} NMR (CD2Cl2): 61.5. Anal.
Calcd for C35H37BF15SiP (812.528): C, 51.74; H, 4.59. Found:
C, 51.53; H, 4.76.
5: orange, crystalline solid, 216 mg, 95%. 1H NMR (CD2Cl2):
4.9 (d, 1H, 1JH-P=430 Hz, tBu3PH), 4.3 (t, 2H, 3JH-H=2 Hz,
FeCp0), 4.1 (s, 5H, FeCp), 4.0 (t, 2H, 3JH-H=2 Hz, FeCp0), 1.6
(d, 27H, 3JH-P=16 Hz, tBu3PH). 11B NMR (CD2Cl2): -20.8.
13C{1H} NMR (CD2Cl2), partial: 148.8 (dm, 1JC-F=238 Hz, o-
C6F5), 138.8 (dm, 1JC-F=245 Hz, p-C6F5), 137.1 (dm, 1JC-F
=
248 Hz, m-C6F5), 71.4 (s, FeCp0), 70.2 (s, FeCp), 68.05 (s,
FeCp0), 38.2 (d, J = 27 Hz, PCMe3), 30.5 (s, PCMe3). 19F
1: 1H NMR (CD2Cl2): 7.32 (m, 2H, o-Ph), 7.21 (tt, 2H,
4
3
3JH-H =7 Hz, JH-H =1 Hz, m-Ph), 7.15 (tt, 1H, JH-H =7
Hz, 4JH-H=1 Hz, p-Ph), 4.80 (d, 1H, 1JH-P=428 Hz, tBu3PH),
1.52 (d, 27H, 3JH-P=16 Hz, tBu3PH). 11B NMR (CD2Cl2): -20.78
(s). 13C{1H} NMR (CD2Cl2), partial: 148.85 (dm, 1JC-F=245
Hz, o-C6F5), 138.88 (dm, 1JC-F=248 Hz, p-C6F5), 137.18 (dm,
1JC-F =241 Hz, m-C6F5), 131.80, 128.62, 128.19 (s, ipso-Ph),
3
NMR (CD2Cl2): -132.7 (d, 6F, JF-F=20 Hz, o-C6F5), -164.3
(t, 3F, 3JF-F=20 Hz, p-C6F5), -167.8 (t, 6F, 3JF-F=18 Hz, m-
C6F5). 31P{1H} NMR (CD2Cl2): 60.8. Anal. Calcd for
C42H36BF15PFe (923.357): C, 54.63; H, 3.93. Found: C, 54.63;
H, 4.21. X-ray quality crystals were grown by slow cooling of a
solution in CH2Cl2.
126.64, 37.98 (d, 1JC-P=27 Hz, PCMe3), 30.25 (s, PCMe3). 19
F
6: off-white powder, 209 mg, 81%. 1H NMR (CD2Cl2): 7.2 (s,
NMR (CD2Cl2): -132.73 (d, 6F, 3JF-F=25 Hz, o-C6F5), -163.94
(t, 3F, 3JF-F=20 Hz, p-C6F5), -167.45 (d, 6F, 3JF-F=19 Hz, m-
C6F5). 31P{1H} NMR (CD2Cl2): 61.49. Anal. Calcd for
C38H33BF15P (816.443): C, 55.90; H, 4.07. Found: C, 55.88;
H, 4.18. X-ray quality crystals were grown by slow cooling of a
solution in chlorobenzene.
1
4H, HAr), 7.37 (m, 2H, o-CCPh), 4.7 (d, 2H, JH-P = 427
3
tBu3PH), 1.6 (d, 54H, JH-P = 16 Hz, tBu3PH). 11B NMR
(CD2Cl2): -20.9 (s). 13C{1H} NMR (CD2Cl2), partial: 143.2
(dm, JC-F = 243 Hz, o-C6F5), 138.2 (dm, JC-F = 244 Hz,
1
1
1
p-C6F5), 136.5 (dm, JC-F=248 Hz, m-C6F5), 131.0, 125.4 (s,
ipso-CAr), 37.4 (d, 1JC-P=26 Hz, PCMe3), 29.8 (s, PCMe3). 19
F
2: white solid, 117 mg, 81%. 1H NMR (C6D5Br): 4.3 (d, 1H,
NMR (CD2Cl2): -132.5 (d, 6F, 3JF-F=25 Hz, o-C6F5), -163.6
1JH-P=434 Hz, tBu3PH), 2.2 (t, 2H, 3JH-H=7 Hz, CH2CCB),
3
3
(t, 3F, JF-F=21 Hz, p-C6F5), -167.2 (t, 6F, JF-F=23 Hz,
m-C6F5). 31P{1H} NMR (CD2Cl2): 61.1 Anal. Calcd for
C70H60B2F30P2 (1554.773): C, 54.08; H, 3.89. Found: C, 54.44;
H, 4.19. Crystals were grown by slow cooling of a solution in
CH2Cl2; due to multiple disordered solvent molecules, the
structure was not suitable for publication, although connectivity
was established.
3
1.6-1.3 (m, 4H, CH3CH2CH2), 0.95 (d, 27H, JH-P=15 Hz,
3
tBu3PH), 0.8 (t, 3H, JH-H = 7 Hz, CH3CH2). 11B NMR
(C6D5Br): -20.5. 13C{1H} NMR (CD2Cl2) partial: 148.3 (dm,
1JC-F=237 Hz, o-C6F5), 138.2 (dm, 1JC-F=243 Hz, p-C6F5),
1
1
136.8 (dm, JC-F =243 Hz, m-C6F5), 37.9 (d, JC-P =26 Hz,
PCMe3), 32.1 (s), 30.2 (s, PCMe3), 22.1 (s), 20.1 (s), 13.7 (s). 19
NMR (C6D5Br): -130.8 (d, 6F, 3JF-F=23 Hz, o-C6F5), -163.1
F
7: 61 mg (91%). 1H NMR (CD2Cl2): 7.45 (m, 2H, o-Ph), 7.36
(m, 1H, p-Ph), 7.27 (m, 2H, p-Ph), 4.94 (d, 1H, 1JH-P=426 Hz,
tBu3PH), 1.60 (d, 27H,, 3JH-P=16 Hz, tBu3PH). 13C{1H} NMR
(CD2Cl2), partial: 150.45 (dm, 1JC-F=230 Hz, o-C6F5), 140.71
3
3
(t, 3F, JF-F=21 Hz, p-C6F5), -166.1 (t, 6F, JF-F=21 Hz,
m-C6F5). 31P{1H} NMR (C6D5Br): 60.5 (s). Anal. Calcd for
C36H37BF15P (796.453): C, 54.29; H, 4.68. Found: C, 53.72; H,
1
1
(dm, JC-F = 246 Hz, p-C6F5), 136.86 (dm, JC-F = 246 Hz,
m-C6F5), 131.80, 128.62, 128.19, 126.64, 38.18 (d, 1JC-P=27 Hz,
PCMe3), 30.45 (s, PCMe3). 19F NMR (CD2Cl2): -121.81 (s, br,
6F, o-C6F5), -158.576 (t, 3F, 3JF-F=20 Hz, p-C6F5), -164.44
(m, 6F, m-C6F5). 27Al NMR (CD2Cl2): 105.18. 31P{1H} NMR
(CD2Cl2): 61.76. Anal. Calcd for C38H33F15AlP (832.614): C,
54.82; H, 4.00. Found: C, 54.58; H, 4.18. X-ray quality crystals
(42) Hair, G. S.; Cowley, A. H.; Jones, R. A.; McBurnett, B. G.;
Voigt, A. J. Am. Chem. Soc. 1999, 121, 4922–4923.
(43) Bartlett, R. A.; Olmstead, M. M.; Power, P. P.; Sigel, G. A. Inorg.
Chem. 1987, 26, 1941–1946.
(44) Deck, P. A.; Beswick, C. L.; Marks, T. J. J. Am. Chem. Soc. 1998,
120, 1772–1784.
(45) Welch, G. C.; Juan, R. R. S.; Masuda, J. D.; Stephan, D. W.
Science 2006, 314, 1124–1126.
of 7 (C6H5Cl) were grown by slow cooling of a solution in
3
(46) Moretti, I.; Torre, G. Synthesis 1970, 3, 141.
(47) Massey, A. G.; Park, A. J. J. Organomet. Chem. 1964, 2, 245–250.
(48) Massey, A. G.; Park, A. J. In Organometallic Synthesis; King,
R. B.; Eisch, J. J., Eds.; Elsevier: New York, 1986; Vol. 3.
(49) Massey, A. G.; Park, A. J.; Stone, F. G. A. Proc. Chem. Soc.
1963, 212.
chlorobenzene.
8: colorless, crystalline solid, which was washed with pentane
1
(2 ꢀ 5 mL) to afford a white solid (152 mg, 85%). H NMR
3
(CD2Cl2): 7.6 (d, 2H, JH-H = 7 Hz, o-BPh), 7.4 (m, 2H,
3
o-CCPh), 7.2 (tt, 2H, JH-H = 7 Hz, JH-H = 1 Hz, m-Ph),
4

Article
Organometallics, Vol. 29, No. 23, 2010 6597
7.1 (m, 3H), 7.0 (tt, 1H, 3JH-H=7 Hz, 4JH-H=1 Hz, p-Ph), 4.8
(d, 1H, 1JH-P=430 Hz, tBu3PH), 1.5 (d, 27H, 3JH-P=16 Hz,
tBu3PH). 11B NMR (CD2Cl2): -17.1. 13C{1H} NMR (CD2Cl2),
isomer), 7.78-6.33 (m, 16H of minor isomer, 14H of major
isomer), 6.45 (d, JH-H = 8 Hz, major isomer), 2.55 (s, 3H,
3
o-C6H4Me of minor isomer), 2.34 (s, 3H, o-C6H4Me of major
isomer), 1.73 (s, 3H, o-C6H4Me of minor isomer), 1.68 (s, 3H, o-
C6H4Me of minor isomer), 1.58 (s, 3H, o-C6H4Me of major
isomer), 0.55 (s, 3H, o-C6H4Me of major isomer). 11B NMR
(CD2Cl2, 215 K): -15.35 (s), -15.75 (s). 19F NMR (CD2Cl2, 215
K): -132.75 (s, br, o-C6F5), -161.60 (m, br, p-C6F5), -165.77 (s,
br, m-C6F5), 166.23 (s, br, m-C6F5). 31P{1H} NMR (CD2Cl2,
215 K): (ratio of minor:major 1:1.75) 30.52 (s, br, major), 27.05
(s, br, minor). 31P{1H} NMR (THF-d8, 215 K): (ratio of minor:
major 1:2.15) 30.80 (s, br, major), 27.41 (s, br, minor). Anal.
Calcd for C47H27BF15P (918.495): C, 61.46; H, 2.96. Found: C,
partial: 148.2 (dm, 1JC-F=246 Hz, o-C6F5), 138.0 (dm, 1JC-F
=
1
243 Hz, p-C6F5), 136.8 (dm, JC-F =249 Hz, m-C6F5), 133.6,
131.5, 128.2, 126.5, 125.9, 123.9, 37.7 (d, 1JC-P=26 Hz, PCMe3),
30.1 (s, PCMe3). 19F NMR (CD2Cl2): -130.9 (m, 6F, o-C6F5), -
165.1 (t, 3F, 3JF-F=20 Hz, p-C6F5), -167.5 (m, 6F, m-C6F5).
31P{1H} NMR (CD2Cl2): 60.9. Anal. Calcd for C38H38BF10P
(726.491): C, 62.83; H, 5.27. Found: C, 62.84; H, 5.49.
9: colorless, microcrystalline solid (263 mg, 49%). 1H NMR
(CD2Cl2): 7.5 (m, 8H, o-BPh þ o-CCPh), 7.2 (tm, 2H, 3JH-H=8
3
Hz, m-CCPh), 7.1 (tm, 1H, JH-H = 7 Hz, m-CCPh), 7.07 (t,
6H, 3JH-H=7 Hz, m-BPh), 6.9 (t, 3H, 3JH-H=7 Hz, p-BPh), 4.6
(d, 1H, 1JH-P=436 Hz, tBu3PH), 1.4 (d, 27H, 3JH-P=16 Hz,
tBu3PH). 11B NMR (C6D5Br): -12.07. 13C{1H} NMR (CD2Cl2),
partial: 134.7 (s), 131.1 (s), 127.9 (s), 126.1 (s), 125.0 (s), 122.6 (s),
37.2 (d, 1JC-P=27 Hz, PCMe3), 29.9 (s, PCMe3). 31P{1H} NMR
(CD2Cl2): 59.1 (s). Anal. Calcd for C38H48BP (546.587): C,
83.50; H, 8.85. Found: C, 83.48; H, 9.20. X-ray quality crystals
were grown by slow evaporation of a solution in CH2Cl2.
Synthesis of [tBu3PSiMe3][Me3SiCCB(C6F5)3] (10). A solu-
tion of B(C6F5)3 (104 mg, 0.2 mmol) in toluene (2 mL) was
added in one portion to a solution of tBu3P (80 mg, 0.4 mmol)
and Me3SiCCSiMe3 (100 mg, 0.6 mmol) in toluene (1 mL). The
reaction mixture yellowed immediately, and during the course of
10 min the mixture became biphasic. Pentane (10 mL) was added
and the bottom layer crystallized. The supernatant was decanted
and the resulting white, microcrystalline solid dried in vacuo (81
61.89; H, 3.12. X-ray quality crystals of 11 (C6H5Br) were
3
grown by slow cooling of a solution in bromobenzene.
12: 98 mg, 87%. 1H NMR (CD2Cl2): 8.3 (d, 1H, 3JH-P=36
Hz, CdC-H), 7.8 (td, 3H, 3JH-H=8 Hz, 5JH-p=2 Hz, p-PhP), 7.6
(td, 6H, 3JH-H=8 Hz, 4JH-p=6 Hz, m-PhP), 7.4 (m, 6H, o-PhP).
11B NMR (CD2Cl2): -16.3 (d, 3JB-P=14 Hz). 13C{1H} NMR
1
(CD2Cl2) partial: 148.1 (dm, JC-F = 236 Hz, o-C6F5), 138.4
1
1
(dm, JC-F = 242 Hz, m-C6F5), 136.5 (dm, JC-F = 246 Hz,
p-C6F5), 134.6 (d, 3JC-P=10 Hz, m-PhP), 134.4 (d, 4JC-P=3 Hz,
p-PhP), 129.6 (d, 2JC-P=12 Hz, o-PhP), 129.3 (d, 3JC-P=5 Hz,
4
5
o-PhC), 127.9 (d, JC-P = 2 Hz, m-PhC), 127.8 (d, JC-P
=
2 Hz, p-PhC), 119.5 (d, JC-P = 86 Hz, P-CdC). 19F NMR
(C6D5Br): -130.6 (d, 6F, 3JF-F=23 Hz, o-C6F5), -160.8 (t, 3F,
3JF-F=21 Hz, p-C6F5), -165.1 (d, 6F, 3JF-F=20 Hz, m-C6F5).
31P {1H} NMR (CD2Cl2): 25.2 (q, 3JP-B=15 Hz). Anal. Calcd
for C47H27BF15P (876.414): C, 60.30; H, 2.42. Found: C, 60.65;
H, 2.72. X-ray quality crystals were grown by slow evaporation
of a solution in CH2Cl2.
1
1
3
mg, 45%). H NMR (CD2Cl2): 1.6 (d, 27H, JH-P = 14 Hz,
tBu3PSiMe3), 0.8 (d, 9H, 3JH-P=5 Hz, tBu3PSiMe3), 0.1 (s, 9H,
CCSiMe3). 11B NMR (CD2Cl2): -21.4. 13C{1H} NMR
13: 120 mg, 58%.1H NMR (CD2Cl2): 8.0 (d, 1H, 3JH-P=39
1
3
(CD2Cl2), partial: 148.2 (dm, JC-F =240 Hz, o-C6F5), 138.4
Hz, CdC-H), 7.9-7.8 (m, 9H), 7.7 (td, 6H, JH-H = 8 Hz,
1
1
4JH-P=3 Hz, m-Ph), 3.9 (m, 2H, Cp0), 3.5 (m, 2H, Cp0), 3.4 (s,
5H, Cp). 11B NMR (CD2Cl2): -16.3 (d, 1JB-P=16 Hz). 13C {1H}
(dm, JC-F = 245 Hz, p-C6F5), 136.4 (dm, JC-F = 250 Hz,
m-C6F5), 41.6 (d, 1JC-P=18 Hz, PCMe3), 31.4 (s, br, PCMe3), 4.6
(d,2JC-P=4 Hz, PSiMe) 0.8(s,SiMe3).19FNMR(CD2Cl2):-312.2
(d, 6F, 3JF-F=22 Hz, o-C6F5), -163.9 (t, 3F, 3JF-F= 21 Hz,
p-C6F5), -167.4 (t, 3F, 3JF-F=23 Hz, m-C6F5). 31P{1H} NMR
(CD2Cl2): 31.2 (s). Anal. Calcd for C38H45BF15Si2P (884.710):
C, 51.59; H, 5.13. Found: C, 51.07; H, 5.21. X-ray quality
crystals were grown by slow cooling of the supernatant liquid;
these crystals were weakly diffracting, connectivity was estab-
lished, but the structure was not suitable for publication.
Synthesis of E-(o-tol)3P(Ph)CdC(H)B(C6F5)3 (11), E-Ph3P-
(R)CdC(H)B(C6F5)3 (R = Ph (12), CpFe(C5H4) (13)), E-Ph3P-
(Ph)CdC(Me)B(C6F5)3 (14), E-R2PH(Ph)CdC(H)B(C6F5)3
(R = Ph (15), C6H2Me3 (16)), E-Ph3P(Ph)CdC(H)BPh(C6F5)2
(18), E-Ph3P(Ph)CdC(H)Al(C6F5)3 (19), E-Ph3P(C4H9)CdC-
(H)Al(C6F5)3 (20), and E-(o-tol)3P(Ph)CdC(H)Al(C6F5)3 (21).
These compounds were prepared in a similar fashion, and thus
only one is detailed. PhCCH (0.3 mL, 23 mmol) was added in
NMR (CD2Cl2) partial: 192.8 (m, CdC-B), 148.7 (dm, 1JC-F
=
232 Hz, o-C6F5), 139.0 (dm, 1JC-F=240 Hz, p-C6F5), 137.3 (dm,
1JC-F = 242 Hz, m-C6F5), 135.2 (d, JC-P = 8 Hz), 134.8 (d,
JC-P=3 Hz), 130.2 (d, JC-P=12 Hz), 121.6 (d, JC-P=88 Hz),
118.6 (d, JC-P=78 Hz), 84.4 (d, JC-P=15 Hz, 1-Cp0), 71.1 (d,
JC-P = 5 Hz, 2-Cp0), 69.8 (s, Cp), 68.1 (s, 3-Cp0). 19F NMR
(CD2Cl2): -131.7 (d, 6F, 3JF-F=22 Hz, o-C6F5), -162.9 (t, 3F,
3JF-F=20 Hz, p-C6F5), -167.2 (d, 6F, 3JF-F=20 Hz, m-C6F5).
31P{1H} NMR (CD2Cl2): 23.4 (d, 1JP-B=16 Hz). Anal. Calcd
for C48H25BF15PFe CH2Cl2 (984.335): C, 55.04; H, 2.45.
Found: C, 55.30; H, 2.89. X-ray quality crystals were grown
by slow cooling of a solution in CH2Cl2.
3
14: colorless crystals (88 mg, 77%). 1H NMR (373 K,
C2D2Cl4): 7.7 (m, 3H, p-PPh), 7.7-7.5 (m, 12H, PPh), 6.9-6.7
(m, 5H, PhCdC), 1.9 (s, br, 3H, CdCMe). 11B NMR (293 K,
CD2Cl2): -13.0 (s, br). 19F NMR (293 K, CD2Cl2): -122.7 (s,
br, 1F, o-C6F5), -128.7 (s, br, 1F, o-C6F5), -130.1 (s, br, 1F, o-
C6F5), -130.8 (s, br, 1F, o-C6F5), -132.4 (d, 1F, 3JF-F=23 Hz,
one portion to a slurry of Ph3P B(C6F5)3 (100 mg, 0.13 mmol) in
3
chlorobenzene (3 mL). After 15 min of stirring the solution
became clear and yellow and was stirred for an additional two
hours, at which point the solvent was removed under reduced
pressure and the resulting powder washed with a 10:1 mixture of
pentane and chlorobenzene to afford an off-white powder (12).
o-C6F5), -132.7 (s, br, 1F, o-C6F5), -162.2 (t, br, 1F, 3JF-F
=
23 Hz, p-C6F5), -162.3 (t, 1F, 3JF-F=21 Hz, p-C6F5), -163.0 (t,
3
br, 1F, JF-F = 21 Hz, p-C6F5), -166.4 to -166.9 (m, 4F,
m-C6F5), -167.1 (t, br, 1F, 3JF-F=21 Hz, m-C6F5), -167.5 (t,
br, 1F, 3JF-F=21 Hz, m-C6F5). 31P{1H} NMR (293 K, CD2Cl2):
16.5 (q, 3JP-B=16 Hz). Anal. Calcd for C45H23BF15P (890.441):
C, 60.70; H, 2.60. Found: C, 60.59; H, 2.94.
1
11: 423 mg, 75%. H NMR (C2D2Cl4, 385 K): 8.18 (d, 1H,
3JH-P=40 Hz, dC-H), 7.85 (dd, 3H, JH-P=14 Hz, JH-H
3
=
7 Hz), 7.67 (t, 3H, 3JH-H=8 Hz), 7.49 (t, 2H, 3JH-H=7 Hz), 7.33
3
3
15: white, microcrystalline solid, 163 mg, 70%. 1H NMR
(dd, 3H, JH-P = 8 Hz, JH-H = 8 Hz), 7.08 (t, 1H, JH-H
=
7 Hz, p-Ph), 6.93 (m, 4H, Ph), 1.80 (s, 9H, PC6H4Me). 11B NMR
(C2D2Cl4, 385 K): -13.55 (d, 3JB-P=16 Hz). 19F NMR (C2D2Cl4,
385 K): -128.83 (d, 6F, 3JF-F=22 Hz, o-C6F5), -160.14 (t, 3F,
3
(CD2Cl2): 8.3 (d, 1H, JH-P = 39 Hz, CdC-H), 7.9 (d, 1H,
1JH-P=225 Hz, Ph2PH), 7.8 (m, 2H), 7.7-7.6 (m, 8H), 7.1 (tm,
1H, 3JH-H=7 Hz, p-CCPh), 7.0 (t, 2H, 3JH-H=7 Hz, m-CCPh),
3JF-F = 20 Hz, p-C6F5), -164.34 (d, 6F, JF-F = 19 Hz,
3
3
6.8 (dm, 2H, JH-H=7 Hz, o-CCPh). 11B NMR (CD2Cl2): -
m-C6F5). 31P{1H} NMR (C2D2Cl4, 385 K): 31.09 (q, JP-B
16 Hz). H NMR (CD2Cl2, 215 K): (ratio of minor:major =
=
16.1 (d, 1JB-P=18 Hz). 13C{1H} NMR (139.06 CD2Cl2), partial:
148.3 (dm, JC-F =248 Hz, o-C6F5), 135.7 (d, JC-P =4 Hz),
134.2 (d, JC-P=10 Hz), 130.7 (d, JC-P=12 Hz), 128.8 (d, JC-P=
3
1
1
1:1.7) 8.49 (d, 1H, 3JH-P=39 Hz, CdC-H, minor isomer), 8.41
(m, 1H, major isomer), 8.06 (dd, 1H, JH-P =12 Hz, JH-H =
3
6 Hz), 128.6 (d, JC-P=3 Hz), 128.5 (d, JC-P=3 Hz). 19F NMR
(CD2Cl2): -132.0 (d, 6F, 3JF-F=23 Hz, o-C6F5), -162.4 (t, 3F,
8 Hz, minor isomer) 7.84 (d,1H, 3JH-P=36 Hz, CdC-H major

6598 Organometallics, Vol. 29, No. 23, 2010
Dureen et al.
3
3
3JF-F = 20 Hz, p-C6F5), -166.8 (t, 6F, JF-F = 21 Hz,
8 Hz), 7.51 (t, 2H, JH-H=7 Hz), 7.38 (dd, 3H, JH-P=7 Hz,
3JH-H=7 Hz), 7.10 (t, 1H, 3JH-H=7 Hz, p-Ph), 6.98 (m, 4H,
Ph), 1.88 (s, 9H, PC6H4Me). 19F NMR (C2D2Cl4, 385 K): -119.35
(s, br, 6F, o-C6F5), -155.63 (t, 3F, 3JF-F=19 Hz, p-C6F5), -161.93
(m, 6F, m-C6F5). 27Al NMR (C2D2Cl4, 385 K): 116.52 (s, br).
31P{1H} NMR (C2D2Cl4, 385 K): 26.13 (s, br). Anal. Calcd for
C47H27F15AlP (934.665): C, 60.40; H, 2.91. Found: C, 59.93; H,
1
m-C6F5). 31P{1H} NMR (CD2Cl2): 14.4 (d, JP-B = 18 Hz).
Anal. Calcd for C38H17BF15P (800.316): C, 57.03; H, 2.14.
Found: C, 57.56; H, 2.56. X-ray quality crystals were grown
by layering a solution in CH2Cl2 with pentane.
16: white solid, 215 mg, 78%. 1H NMR (CD2Cl2): 8.0 (d, 1H,
1JH-P = 461 Hz, PH), 7.9 (d, 1H, JH-P = 42 Hz, CdC-H),
3
3.38. X-ray quality crystals of 21 (CH2Cl2) were grown by slow
3
7.1-7.0 (m, 5H), 7.0 (d, 4H, JH-H=5 Hz), 2.4 (s, 12H, p-Me),
2.3 (s, 6H, o-Me). 11B NMR (CD2Cl2): -15.6 (d, 3JB-P=18 Hz).
13C{1H} NMR (CD2Cl2) partial: 181.0 (m, CdC-B), 147.9 (dm,
1JC-F = 236 Hz, o-C6F5), 145.8 (d, JC-P = 3 Hz), 143.8 (d,
evaporation of a solution in CH2Cl2.
Synthesis of E-(C6H2tBu3)PH2(Ph)CdC(H)B(C6F5)3 (17). To
a solution of (2,4,6-C6H2tBu3)PH2 (43 mg, 0.15 mmol) and
B(C6F5)3 (79 mg, 0.15 mmol) in CH2Cl2 (2 mL) was added in one
portion PhCCH (0.2 mL, 2.1 mmol). The reaction mixture went
from colorless to a light peach upon this addition. The solution
was layered with pentane (5 mL) and cooled to -35 °C over-
J
C-P=10 Hz), 138.4 (dm, 1JC-F=250 Hz, p-C6F5), 136.5 (dm,
1JC-F =242 Hz, m-C6F5), 131.4 (d, JC-P =11 Hz), 128.4 (d,
JC-P=7 Hz), 128.2 (d, JC-P=3 Hz), 127.8 (d, JC-P=10 Hz),
112.9, 112.2, 21.3 (d, 5JC-P=8 Hz, o-CH3), 20.9 (s, p-CH3). 19
F
night, affording clear, colorless crystals (120 mg, 90%). 1H
NMR (CD2Cl2): -132.4 (d, 6F, 3JF-F = 24 Hz, o-C6F5), -162.5
4
NMR (CD2Cl2): 8.1 (s, 1H, CdC-H), 7.8 (d, 2H, JH-P
3
3
=
(t, 3F, JF-F=19 Hz, p-C6F5), -166.8 (d, 6F, JF-F=24 Hz,
m-C6F5). 31P{1H} NMR (CD2Cl2): 12.9 (q, JP-B = 18 Hz).
3
4 Hz, m-CAr-H), 7.4-7.2 (m, 4H), 7.0-6.9 (m, 3H), 1.5 (s,
o-tBu), 1.4 (s, p-tBu). 11B NMR (CD2Cl2): -16.3 (d, 1JB-P=16
Hz). 13C{1H} NMR (CD2Cl2) partial: 181.3 (q, 1JC-B=45 Hz,
CdC-B), 159.8 (d, JC-P=2 Hz), 159.2 (d, JC-1 P=2 Hz), 148.4
Anal. Calcd for C44H29BF15P (884.478): C, 59.75; H, 3.30.
Found: C, 59.80; H, 3.09. X-ray quality crystals were grown
by slow cooling of a solution in CH2Cl2.
1
18: white, microcrystalline solid, 220 mg, 92%. 1H NMR
(dm, JC-F = 238 Hz, o-C6F5), 139.0 (dm, JC-F = 250 Hz,
p-C6F5), 136.9 (dm, 1JC-F=248 Hz, m-C6F5), 135.9 (d, JC-P
=
3
(CD2Cl2): 8.3 (d, 1H, JH-P = 36 Hz, CdC-H), 7.7 (tm, 3H,
3JH-H=8 Hz), 7.5 (tm, 6H, 3JH-H=8 Hz), 7.4-7.3 (m, 6H), 7.3
=
19 Hz), 129.3 (d, JC-P=3 Hz), 129.2 (d, JC-P=1 Hz), 128.5 (d,
C-P=6 Hz), 125.7 (d, JC-P=13 Hz), 119.3 (d, JC-P=65 Hz),
102.2 (d, JC-P=76 Hz), 38.9 (d, JC-P=4 Hz, o-CMe3), 36.4 (s,
(d, br, 2H, 3JH-H=7 Hz), 7.2-7.0 (m, 4H), 6.9 (t, 2H, 3JH-H
J
8 Hz), 6.8 (d, 2H, 3JH-H=7 Hz). 11B NMR (CD2Cl2): -12.6 (s,
br). 13C{1H} NMR (CD2Cl2) partial: 186.2 (m, CdC-B), 147.6
(dm, JC-F = 237 Hz, o-C6F5), 138.0 (dm, JC-F = 244 Hz,
p-CMe3), 34.1 (s, o-CMe3), 30.9 (s, p-CMe3). 19F NMR
3
1
1
(CD2Cl2): -131.6 (d, 6F, JF-F =23 Hz, o-C6F5), -162.4 (t,
3
3
p-C6F5), 136.5 (dm, 1JC-F=248 Hz, m-C6F5), 131.8 (d, JC-P
=
3F, JF-F = 20 Hz, p-C6F5), -166.8 (d, 6F, JF-F = 22 Hz,
m-C6F5). 31P{1H} NMR (CD2Cl2): -31.1 (q, JP-B =17 Hz).
3
17 Hz), 134.5 (d, JC-P =9 Hz), 134.2 (s), 133.2 (s), 130.1 (d,
JC-P=6 Hz), 129.5 (d, JC-P=13 Hz), 127.7(s), 127.6 (s), 126.6
(s), 124.0 (s), 120.5 (s), 119.7 (s), 117.4 (d, JC-P = 86 Hz,
Anal. Calcd for C44H37BF15P (892.542): C, 59.21; H, 4.18.
Found: C, 59.13; H, 4.60. The crystalline product was suitable
for X-ray diffraction.
1
3
P-CdC). 19F NMR (CD2Cl2): -128.8 (d, 4F, JF-F =23 Hz,
o-C6F5), -163.5 (t, 2F, 3JF-F=20 Hz, p-C6F5), -166.7 (d, 4F,
3JF-F=20 Hz, m-C6F5). 31P{1H} NMR (CD2Cl2): 24.9 (s, br).
Anal. Calcd for C50H30BF15P2 (988.526): C, 60.75; H, 3.06.
Found: C, 61.09; H 3.16. X-ray quality crystals were grown by
layering a solution in CH2Cl2 with pentane.
Synthesis of [(H)CdC(Ph)Mes2PC6F4B(C6F5)2]2 (22) and E-
Ph2PCH2CH2PPh2(Ph)CdC(H)B(C6F5)3 (23). These com-
pounds were prepared in a similar fashion, and thus only one
preparation is detailed. To a solution of Mes2P-C6F4-B(C6F5)2
(35 mg, 0.05 mmol) in toluene (3 mL) was added in one portion
PhCCH (0.1 mL, 0.9 mmol). After 30 min pentane (15 mL) was
added to precipitate an off-white powder, which was dried in vacuo.
22: 30 mg, 81%. 1H NMR (CD2Cl2): 8.7 (m, br, P-CdC(H)-
B), 7.3 (m, br, 2H), 7.0 (m, br, 3H), 6.7 (s, br, 2H), 2.2 (s, br, 3H),
2.0 (m, br, 3H), 1.9 (m, br, 3H). 11B NMR (CD2Cl2): -13.2 (s,
br). 19F NMR (CD2Cl2): -129 0.4 (s, br, 2F, C6F4), -130.6 (m,
br, 2F, C6F4), -134.1 (s, br, 2F, C6F4), -135.5 (m, 4F, o-C6F5), -
136.0 (m, 4F, o-C6F5), -137.0 (m, br, 2F, C6F4), -159.3 (s, br, 2F,
p-C6F5), -159.7 (s, br, 2F, p-C6F5), -165.0 to -165.5 (m, 8F, m-
C6F5). 31P{1H} NMR (CD2Cl2): -37.2 (m, br). Anal. Calcd for
C72H56B2F28P2 (1536.766): C, 56.27; H, 3.67. Found: C, 56.26; H,
3.26. X-ray quality crystals were grown from slow evaporation of a
solution in toluene/CH2Cl2.
19: 1H NMR (CD2Cl2): 8.2 (d, 1H, 3JH-P=39 Hz, CdC-H),
7.8 (tm, 3H, 3JH-H=7 Hz, p-PPh), 7.6 (td, 6H, 3JH-H = 7 Hz,
4JH-H=4 Hz, m-PPh), 7.4 (dd, 6H, 3JH-P=12 Hz, 3JH-H=7 Hz,
o-PPh), 7.08 (tm, 1H, 3JH3-H=7 Hz, p-Ph), 6.9 (t, 2H, 3JH-H
=
7 Hz, m-Ph), 6.7 (d, 6H, JH-H=7 Hz, o-Ph). 13C{1H} NMR
(CD2Cl2) partial: 149.5 (dm, JC-F = 231 Hz, o-C6F5), 140.2
1
1
1
(dm, JC-F = 244 Hz, p-C6F5), 136.1 (dm, JC-F = 255 Hz,
m-C6F5), 134.6 (s), 134.5 (s), 134.4 (s), 129.7 (d, JC-P=13 Hz),
129.5 (d, JC-P=5 Hz), 128.1 (d, JC-P=13 Hz), 127.7 (d, JC-P=
2 Hz), 119.3 (d, JC-P=85 Hz). 19F NMR (CD2Cl2): -121.8 (d,
3
3
6F, JF-F = 20 Hz, o-C6F5), -157.9 (t, 3F, JF-F = 20 Hz,
p-C6F5), -164.2 (m, 6F, m-C6F5). 27Al NMR (CD2Cl2): 115.0
(s). 31P{1H} NMR (CD2Cl2): 23.4 (s, br). Anal. Calcd for
C44H21F15AlP (892.584): C, 59.21; H, 2.37. Found: C, 59.68;
H, 2.51. X-ray quality crystals were grown from layering a
solution in CH2Cl2 with pentane.
23: white microcrystalline solid: 163 mg, 56%. 1H NMR
(CD2Cl2): 8.34 (d, 1H, 3JH-P = 35 Hz, CdC-H), 7.8 (tm, 2H,
3JH-H = 8 Hz), 7.6 (tm, 4H, 3JH-H = 8 Hz), 7.6-7.5 (m, 4H),
7.4-7.3 (m, 6H), 7.2-7.1 (m, 4H), 7.1 (tm, 1H, 3JH-H = 8 Hz),
6.9 (t, 2H, 3JH-H = 7 Hz), 6.5 (d, 2H, 3JH-H = 8 Hz), 2.3 (m,
2H, R2PCH2CH2PR3), 2.0 (m, 2H, R2PCH2CH2PR3). 11B
1
20: colorless crystals, 112 mg, 42%. H NMR (CD2Cl2): 7.9-
7.8 (m, 3H), 7.8 (d, 3JH-H=41 Hz P-CdC(H)-Al), 7.7-7.6 (m, 12
H), 2.4 (m, 2H, CdC-CH2), 0.8-0.7 (m, 4H, CH2CH2CH3), 0.5 (t,
3H, 3JH-H=7 Hz, CH3). 13C{1H} NMR (CD2Cl2) partial: 181 (m,
3
NMR (CD2Cl2): -16.3 (d, JB-P = 14 Hz). 13C{1H} NMR
1
(CD2Cl2) partial: 148.5 (dm, JC-F = 249 Hz, o-C6F5), 138.7
1
br, CdC-Al), 150.4 (dm, JC-F = 231 Hz, o-C6F5), 141.0 (dm,
1
1
1JC-F=240 Hz, p-C6F5), 137.0 (dm, 1JC-F=251 Hz, m-C6F5), 135.1
(d, JC-P=3 Hz), 134.8 (d, JC-P=10 Hz), 132.4 (d, JC-P=47 Hz),
(dm, JC-F = 245 Hz, p-C6F5), 136.9 (dm, JC-F = 244 Hz,
m-C6F5), 136.5 (d, JC-P = 12 Hz), 135.0 (d, JC-P = 3 Hz), 133.9
(d, JC-P = 9 Hz), 132.9 (d, JC-P = 18 Hz), 130.4 (d, JC-P = 12
Hz), 129.8, 129.3, 129.2, 128.8 (d, JC-P = 5 Hz), 128.5 (d, JC-P
= 5 Hz), 128.3 (d, JC-P = 3 Hz), 120.2, 20.4 (dd, 1JC-P = 51 Hz,
130.5 (d, JC-P=14 Hz), 120.6 (d, JC-P=87 Hz), 36.2 (d, JC-P
=
21Hz),33.1(s),22.9(s),13.5(s).19FNMR(CD2Cl2):-121.9 (d, 6F,
3JF-F=20 Hz, o-C6F5),-157.3 (t, 3F, 3JF-F=20 Hz, p-C6F5),-163.8
(m, 6F, m-C6F5). 27Al NMR (CD2Cl2): 114.7 (s). 31P{1H} NMR
(CD2Cl2): 23.0 (s, br). Anal. Calcd for C42H25F15AlP (892.584):
C, 57.81; H, 2.89. Found: C, 57.59; H 3.27. The product crystals
were suitable for X-ray diffraction.
3JC-P = 27 Hz), 19.9 (dd, 1JC-P = 18 Hz, 3JC-P = 6 Hz). 19
F
NMR (CD2Cl2): -131.7 (d, 6F, 3JF-F = 23 Hz, o-C6F5), -162.6 (t,
3
3
3F, JF-F = 21 Hz, p-C6F5), -166.8 (d, 6F, JF-F =22 Hz,
m-C6F5). 31P{1H} NMR (CD2Cl2): 24.97 (m, P-CdC-B) -10.5
(d, 3JP-P=45 Hz, -CH2PPh2). Anal. Calcd for C50H30BF15P2
(988.526): C, 60.75; H, 3.06. Found: C, 61.09; H, 3.16.
1
21: 73 mg, 84%. H NMR (C2D2Cl4, 385 K): 8.05 (d, 1H,
=
3
3JH-P=43 Hz, dC-H), 7.79 (s, br, 3H), 7.70 (t, 3H, JH-H

Article
Synthesis of E-(CH2PPh2(Ph)CdC(H)B(C6F5)3)2 (24). PhCCH
(0.1 mL, 0.9 mmol) was added in one portion to a slurry of
(CH2PPh2)2 (50 mg, 0.125 mmol) and B(C6F5)3 (128.5 mg, 0.25
mmol) in CH2Cl2 (5mL). Thesolutionwasstirredfor∼2 h, resulting
in a white precipitate. The supernatant solvent was decanted and the
powder dried under reduced pressure (180 mg, 89%). The product
was not sufficiently soluble in a variety of deuterated solvents (d8-
THF, CD2Cl2, C6D5Br) to allow for characterization by NMR
Organometallics, Vol. 29, No. 23, 2010 6599
solid to be the isomers resulting from deprotonation (27a, 84%
by 19F NMR) and addition (27b, 16%). Recrystallization from
bromobenzene afforded only the isomer formed from deproto-
nation as colorless crystals (82 mg, 57%). 1H NMR (CD2Cl2):
7.6 (tt, 1H, 3JH-H = 7 Hz, 4JH-H = 2 Hz), 7.5 (tm, 2H, 3JH-H
=
7 H, m-Ph), 7.4-7.3 (m, 2H), 7.3-7.2 (m, 5H) 6.40 (s, br, 1H,
NH), 4.0 (s, 2H, NCH2Ph), 2.6 (s, 6H, N(CH3)2), 1.29 (s, 12H,
Me). 11B NMR (CD2Cl2): -20.8. 13C{1H} NMR (CD2Cl2),
1
spectroscopy. Anal. Calcd for C78H36B2F30P2 CH2Cl2 (1711.602):
partial: 148.0 (dm, JC-F = 250 Hz, o-C6F5), 138.5 (dm,
3
1
C, 55.44; H, 2.24. Found: C, 55.95; H, 2.42. X-ray quality crystals
were grown from the undisturbed supernatant solution in CH2Cl2.
Synthesis of E-HCtCC6H4C(PPh3)dC(H)B(C6F5)3 (25). To
1JC-F = 236 Hz, p-C6F5), 136.7 (dm, JC-F = 250 Hz, m-
C6F5), 131.4 (s), 131.3 (s), 130.6 (s), 129.9 (s), 128.8 (s), 127.4
(s), 126.2 (s), 125.8 (s), 63.2 (s, NCH2Ph), 43.6 (s, N(CH3)2). 19
F
a slurry of Ph3P B(C6F5)3 (151 mg, 0.2 mmol) in CH2Cl2 (10
3
NMR (CD2Cl2): -133.2 (d, 6F, 3JF-F = 25 Hz, o-C6F5), -162.3 (t,
3
3
mL) was added in one portion 1,4-diethynylbenzene (26 mg, 0.2
mmol). The reaction mixture yellowed slightly and was then
stirred overnight, after which point the Ph3P B(C6F5)3 had
3F, JF-F=21 Hz, p-C6F5), -166.4 (t, 6F, JF-F=22 Hz, m-
C6F5). Anal. Calcd for C35H19BNF15 (749.332): C, 56.10; H,
2.56; N, 1.87. Found: C, 55.96; H, 2.67; N, 2.03.
3
dissolved completely. The volume was reduced to half the
original volume in vacuo, layered with pentane (5 mL), and
cooled to -35 °C overnight to afford colorless crystals (170 mg,
97%). 1H NMR (CD2Cl2): 8.4 (d, 1H, 3JH-P = 35 Hz, CdC-H),
7.8 (td, 3H, 3JH-H = 7 Hz, 5JH-P = 2 Hz, p-PhP), 7.6 (td, 6H,
3JH-H = 8 Hz, 4JH-P = 4 Hz, m-PhP), 7.5 (m, 6H), 7.1 (d, 2H,
3JH-H = 8 Hz), 6.5 (dd, 2H, 3JH-H = 8 Hz, 4JH-p = 2 Hz), 3.2
(s, 1H, CCH). 11B NMR (CD2Cl2): -16.3 (d, 3JB-P = 14 Hz).
Synthesis of [(tBu)HNdC(R)Ph][PhCCB(C6F5)3] (R = H
(28), Ph (29)). These compounds were prepared in a similar
fashion, and thus only one preparation is detailed. A solution of
B(C6F5)3 (42 mg, 0.08 mmol) in toluene (3 mL) was added
dropwise to a solution of tert-butylbenzylideneimine (14 mg,
0.09 mmol) and PhCCH (0.1 mL, 1.1 mmol) in toluene (4 mL) at
room temperature. The reaction mixture turned bright yellow
and was left undisturbed for 2 days, affording large colorless
crystals of 28 with cocrystallized toluene (52 mg, 73%). 1H
NMR (CD2Cl2): 9.7 (s, br, 1H, CdNH), 8.4 (s, 1H, C(H)dN),
8.0 (dm, 2H, 3JH-H = 8 Hz), 7.9 (tm, 1H, 3JH-H = 7 Hz), 7.7
(tm, 2H, 3JH-H = 8 Hz), 7.2 (m, 2H), 7.1 (m, 3H), 1.5 (s, 9H,
tBu). 11B NMR (CD2Cl2): -20.8 (s). 13C{1H} NMR (CD2Cl2),
partial: 167.9 (s, CdN), 148.8 (dm, 1JC-F = 235 Hz), 140.3 (s),
138.8 (dm, 1JC-F = 245 Hz), 133.2 (dm, 1JC-F = 250 Hz), 132.5
(s), 131.6 (s), 131.2 (s), 129.6 (s), 128.8 (s), 128.7 (s), 127.2 (s),
1
13C{1H} NMR (CD2Cl2) partial: 183.6 (q, JC-B=50 Hz, Cd
C-B) 148.0 (dm, 1JC-F = 237 Hz, o-C6F5), 138.5 (dm, 1JC-F
=
244 Hz, m-C6F5), 136.5 (dm, 1JC-F = 255 Hz, p-C6F5), 135.6 (d,
JC-P = 15 Hz), 134.5 (s), 134.5 (s), 131.9 (s), 131.5 (d, JC-P
=
3 Hz), 129.8 (d, JC-P = 13 Hz), 129.3 (d, 3JC-P = 6 Hz), 123.0
(s), 122.5 (s), 121.8 (d, JC-P=3 Hz), 119.5 (s), 118.7 (s), 82.0
(s, CCH), 78.0 (s, CCH). 19F NMR (CD2Cl2): -131.6 (d, 6F,
3JF-F=23 Hz, o-C6F5), -162.5 (t, 3F, 3JF-F = 21 Hz, p-C6F5), -
166.8 (d, 6F, 3JF-F=20 Hz, m-C6F5). 31P{1H} NMR (CD2Cl2):
25.2 (q, 3JP-B=14 Hz). Anal. Calcd for C46H21BF15P (900.436):
C, 61.36; H, 2.35. Found: C, 61.44; H, 2.62. X-ray quality
crystals were grown by slow cooling of a solution in CH2Cl2.
Synthesis of [tBu3PH][(C6F5)3BCCC6H4C(PPh3)dC(H) B-
(C6F5)3] (26). CH2Cl2 (3 mL) was added to an intimate mixture
of 25 (100 mg, 0.1 mmol), tBu3P (40 mg, 0.2 mmol), and
B(C6F5)3 (57 mg, 0.1 mmol). After dissolution the reaction
mixture was immediately layered with pentane (15 mL). After
∼16 h, off-white crystals formed and were subsequently dried
under reduced pressure (148 mg, 83%). 1H NMR (CD2Cl2): 8.3
(d, 1H, 3JH-P = 36 Hz, CdC-H), 7.8 (tm, 3H, 3JH-H = 7 Hz, p-
127.1 (s), 125.8 (s), 125.6 (s), 63.7 (s, CMe3), 28.5 (s, CMe3). 19
F
NMR (CD2Cl2): -132.6 (d, 6F, 3JF-F = 24 Hz, o-C6F5), -163.1 (t,
3
3
3F, JF-F = 20 Hz, p-C6F5), -166.8 (d, 6F, JF-F = 21 Hz,
m-C6F5). Anal. Calcd for C37H21BNF15 C7H8 (867.510): C,
60.92; H, 3.37; N, 1.61. Found: C, 60.70; H, 3.32; N, 1.65.
29: light yellow, crystalline solid (54 mg, 73%). 1H NMR
(C2D2Cl4): 9.1 (s, br, 1H, NH), 7.9 (t, 1H, 3JH-H = 8 Hz), 7.8 (t,
3
2H, 3JH-H=8 Hz), 7.7 (t, 2H, 3JH-H=8 Hz), 7.6 (t, 2H, 3JH-H
=
8 Hz), 7.4 (d, 2H, 3JH-H = 8 Hz), 7.3 (d, 2H, 3JH-H = 8 Hz), 7.3
(m,2H),7.2(m,3H),1.4(s,9H,tBu).11BNMR(C2D2Cl4):-20.8 (s).
13C{1H} NMR (C2D2Cl4), partial: 183.8 (s, NdC), 148.1 (dm,
1JC-F = 242 Hz, o-C6F5), 138.1 (s), 137.4 (dm, 1JC-F = 245 Hz,
p-C6F5), 136.3 (dm, 1JC-F = 242 Hz, m-C6F5), 134.4 (s), 132.2
(s), 131.3 (s), 130.25 (s), 129.7 (s), 129.1 (s), 128.9 (s), 128.7 (s),
3
4
PhP), 7.6 (td, 6H, JH-H = 8 Hz, JH-P = 3 Hz, m-PhP), 7.4
(dd, 6H, JH-P = 13 Hz, JH-H = 8 Hz, o-PhP), 6.8 (d, 2H,
=
3
3
3JH-H=8 Hz, -C6H4-), 6.3 (dd, 2H, JH-H=8 Hz, JH-P
127.9 (s), 126.9 (s), 126.1 (s), 64.7 (s, CMe3), 28.3 (s, CMe3). 19
F
3
4
1
2 Hz, -C6H4-), 5.0 (d, 1H, JH-P = 428 Hz), 1.6 (d, 27H,
3JH-P = 16 Hz, tBu3PH). 11B NMR (CD2Cl2): -16.3 (s, br,
P-CdC-B), -20.9 (s, CC-B). 13C{1H} NMR (CD2Cl2) partial:
183.6 (m, CdC-B), 148.8 (dm, 1JC-F = 235 Hz, o-C6F5), 138.9
(dm, 1JC-F = 255 Hz, m-C6F5), 137.0 (dm, 1JC-F = 248 Hz, p-
C6F5), 135.2 (d, JC-P = 10 Hz), 135.0 (d, JC-P = 3 Hz), 132.5 (d,
JC-P = 13 Hz), 131.1 (s), 130.3 (d,, JC-P = 13 Hz), 129.4 (d,
JC-P = 4 Hz), 128.1 (s, br), 124.9 (s, br), 124 (s, br), 120.6 (s),
NMR (C2D2Cl4):-134.7 (d, 6F, 3JF-F =24Hz,o-C6F5),-162.1 (t,
3F, 3JF-F=21 Hz, p-C6F5), -165.8 (d, 6F, 3JF-F=21 Hz, m-
C6F5). Anal. Calcd for C43H25BNF15 (851.467): C, 60.66; H,
2.96; N, 1.65. Found: C, 60.57; H, 2.71; N, 1.66. X-ray quality
crystals were grown by slow cooling of a solution in bromo-
benzene.
Synthesis of [tBuNCN(H)C(Ph)dC(H)tBu][PhCCB(C6F5)3] (30).
A solution of PhCCH (40 mg, 0.39 mmol) in CH2Cl2 (1 mL) was
added in one portion to a solution of tBuNCNtBu (28 mg,
0.2 mmol) and B(C6F5)3 (120 mg, 0.23 mmol) in CH2Cl2 (3 mL).
The reaction became bright red after the addition. The solvent
was removed under reduced pressure, and the resulting solid
dissolved in chlorobenzene (1 mL) and layered with pentane
(4 mL). The layered mixture was cooled to -35 °C overnight to
afford colorless crystals (108 mg, 64%). 1H NMR (CD2Cl2): 7.6
119.4 (s), 38.2 (d, 1JC-P = 30 Hz, PCMe3), 30.5 (s, PCMe3). 19
F
NMR (CD2Cl2): -131.5 (d, 6F, 3JF-F = 23 Hz, o-C6F5), -132.6
(d, 6F, 3JF-F = 23 Hz, o-C6F5), -162.7 (t, 3F, 3JF-F = 21 Hz, p-
3
C6F5), -163.9 (t, 3F, JF-F = 21 Hz, p-C6F5), -166.7 (d, 6F,
3
3JF-F = 23 Hz, m-C6F5), -167.4 (d, 6F, JF-F = 21 Hz, m-
C6F5). 31P{1H} NMR (CD2Cl2): 61.7 (s, tBu3PH), 24.7 (m, P-
CdC-B). Anal. Calcd for C76H48B2F30P2 (1614.743): C, 56.53;
H, 3.00. Found: C, 56.93; H, 3.27.
(tt, 1H, 3JH-H=7 Hz, 5JH-H=1 Hz, p-Ph), 7.5 (tm, 2H, 3JH-H
=
3
Synthesis of [PhCH2NMe2H][PhCCB(C6F5)3] (27a). A solu-
tion of B(C6F5)3 (100 mg, 0.2 mmol) in CH2Cl2 (3 mL) was
added to a mixture of PhCH2NMe2 (27 mg, 0.2 mmol) and
PhCCH (20 mg, 0.2 mmol) in CH2Cl2 (3 mL) in one portion. The
solvent was removed under reduced pressure, and the white
residue washed with pentane (5 mL) and dried in vacuo to afford
a white solid (136 mg, 94%). NMR spectroscopy revealed this
7 Hz, m-Ph), 7.4 (dm, 2H, JH-H = 7 Hz, o-Ph), 7.3 (m, 3H),
7.19 (t, 2H, 3JH-H = 7 Hz), 7.1 (m, 1H), 6.0 (s, br, 1H, NH), 4.69
(s, 1H, CdCH), 1.45 (s, 9H, tBu), 1.29 (s, 9H, tBu). 11B NMR
(CD2Cl2): -20.9. 13C{1H} NMR (CD2Cl2), partial: 172.3 (s,
NCN), 148.3 (dm, 1JC-F = 231 Hz, o-C6F5), 138.3 (dm, 1JC-F
=
1
243 Hz, p-C6F5), 136.5 (dm, JC-F =248 Hz, m-C6F5), 134.6,
134.1, 132.8, 131.1, 129.8, 129.7, 128.5, 127.8, 127.5,

6600 Organometallics, Vol. 29, No. 23, 2010
Dureen et al.
127.3, 126.4, 125.7, 63.1 (s, CMe3), 56.0 (s, CMe3), 29.0 (s,
CMe3), 28.0 (s, CMe3). 19FNMR(CD2Cl2):-132.6 (d, 6F, 3JF-F
placed under an N2 stream, thus maintaining a dry, O2-free
environment for each crystal. The data were collected on a
Bruker Apex II diffractometer employing Mo KR radiation (λ=
=
24 Hz, o-C6F5), -163.8 (t, 3F, 3JF-F=21 Hz, p-C6F5), -167.3 (t,
6F, JF-F = 20 Hz, m-C6F5). Anal. Calcd for C43H32BN2F15
3
˚
0.71073 A). Data collection strategies were determined using
Bruker Apex software and optimized to provide >99.5%
complete data to a 2θ value of at least 55°. The data were
collected at 150((2) K for all crystals. The frames were inte-
grated with the Bruker SAINT software package using a
narrow-frame algorithm. Data were corrected for absorption
effects using the empirical multiscan method (SADABS). Non-
hydrogen atomic scattering factors were taken from the litera-
ture tabulations.50 The heavy atom positions were determined
using direct methods employing the SHELXTL direct methods
routine. The remaining non-hydrogen atoms were located from
successive difference Fourier map calculations. The refinements
were carried out by using full-matrix least-squares techniques on
F, minimizing the function w(Fo - Fc)2 where the weight w is
defined as 4Fo2/2σ(Fo2) and Fo and Fc are the observed and
calculated structure factor amplitudes, respectively. In the final
cycles of each refinement, all non-hydrogen atoms were assigned
anisotropic temperature factors in the absence of disorder or
insufficient data. In the latter cases atoms were treated isotro-
pically. C-H atom positions were calculated and allowed to ride
on the carbon to which they are bonded assuming a C-H bond
(872.530): C, 59.19; H, 3.70; N, 3.21. Found: C 59.80; H, 3.58; N,
3.28. X-ray quality crystals were grown by slow cooling of a
solution in chlorobenzene.
Synthesis of [ItBuH][PhCCB(C6F5)3] (31). A solution of
PhCCH (40 mg, 0.4 mmol) and 1,3-di-tert-butylimidazol-2-
ylidene (ItBu) (54 mg, 0.3 mmol) in toluene (5 mL) was cooled
to -78 °C, at which point B(C6F5)3 (153 mg, 0.3 mmol) in
toluene (5 mL) was added in one portion, and the solution was
shaken until all of the borane had dissolved and a white
precipitate formed. The solution was warmed to room tempera-
ture, and the solvent removed under reduced pressure. The solid
was washed with pentane (15 mL), dissolved in bromobenzene
(10 mL), and filtered through Celite. Layering the solution with
pentane (10 mL) resulted in the formation of white crystals (100 mg) of
the product with one equivalent of cocrystallized bromoben-
zene. Cooling of the mother liquor yielded an additional crop of
crystals (52%) for an overall yield of 54%. 1H NMR (CD2Cl2):
8.1 (m, 1H, NdC(H)N), 7.5 (m, 1H), 7.4 (d, 2H, 3JH-H = 2 Hz,
C(H)dC(H)), 7.3 (m, 2H), 7.2 (m, 2H), 1.6 (s, 18H, CMe3). 11
B
NMR (CD2Cl2): -20.9. 13C{1H} NMR (CD2Cl2), partial: 148.9
(dm, 1JC-F = 241 Hz, o-C6F5), 138.9 (dm, 1JC-F = 244 Hz, p-
C6F5), 137.4 (dm, 1JC-F = 248 Hz, m-C6F5), 132.0, 129.5 (s, br,
NC(H)N), 128.4 (s), 128.0 (s), 127.5 (s), 121.2 (s, C(H)dC(H)),
61.5 (s, CMe3), 30.0 (s, CMe3). 19F NMR (CD2Cl2): -132.6 (d,
6F, 3JF-F = 24 Hz, o-C6F5), -163.7 (t, 3F, 3JF-F = 21 Hz, p-
C6F5), -167.3(t, 6F, 3JF-F = 22 Hz m-C6F5). Anal. Calcd for
C43H29BN2F15Br (949.410): C, 54.40; H, 3.08; N, 2.95. Found:
C, 54.87; H, 3.37; N, 2.86. X-ray quality crystals were grown
from slow cooling of a solution in THF.
˚
length of 0.95 A. H atom temperature factors were fixed at 1.20
times the isotropic temperature factor of the C atom to which
they are bonded. The H atom contributions were calculated, but
not refined. The locations of the largest peaks in the final
difference Fourier map calculation as well as the magnitude of
the residual electron densities in each case were of no chemical
significance.
Results and Discussion
Synthesis of E-Me2S(Ph)CdC(H)B(C6F5)3 (32). To a solution
of Me2S B(C6F5)3 (50 mg, 0.09 mmol) in CH2Cl2 (1.5 mL) was
Phosphine/Borane FLPs: Deprotonation of Alkynes. We
have previously communicated that the reaction of PhCCH
with a mixture of tBu3P and B(C6F5)3 in toluene at -35 °C
results in the immediate formation of [tBu3PH][PhCCB(C6F5)3]
(1a) (Scheme 2).51 The corresponding reactions of tBu3P and
3
added dropwise PhCCH (40 mg, 0.4 mmol). The reaction
mixture reddened slightly, was layered with pentane (5 mL),
and was placed in a -35 °C freezer. After 24 h colorless crystals
had formed, the solvent was decanted, and the crystals were
dried in vacuo to afford a crystalline product (52 mg, 88%). 1H
NMR (CD2Cl2): 8.4 (s, 1H, CdC-H), 7.4 (t, 1H, 3JH-H = 7 Hz,
p-Ph), 7.3 (t, 2H, 3JH-H = 7 Hz, m-Ph), 6.9 (d, 2H, 3JH-H = 7
Scheme 2. Synthesis of 1-9
Hz, o-Ph), 2.6 (s, 6H, SCH3). 11B NMR (CD2Cl2): -16.2 (s). 19
F
NMR (CD2Cl2): -131.9 (d, 6F, 3JF-F=22 Hz, o-C6F5), -161.6
(t, 3F, 3JF-F=21 Hz, p-C6F5), -166.2 (t, 6F, 3JF-F=23 Hz, m-
C6F5). Anal. Calcd for C28H12BF15S (676.256): C, 49.73; H,
1.79. Found: C, 49.08; H, 1.89.
Synthesis of E-(PhCH2)2S(Ph)CdC(H)B(C6F5)3 (33). To a
solution of B(C6F5)3 (150 mg, 0.29 mmol) and dibenzylsulfide
(130 mg, 0.54 mmol) in toluene (1.5 mL) was added dropwise
PhCCH (30 mg, 0.3 mmol). The reaction mixture reddened
slightly, was layered with hexanes (5 mL), and was placed in a -
35 °C freezer. After 24 h colorless crystals formed (237 mg,
95%). NMR studies revealed solutions of the product in CD2Cl2
were spectroscopically pure initially, but would decompose over
∼30 min to afford starting materials and other unidentified
products. 1H NMR (CD2Cl2): 8.4 (s, 1H, CdC-H), 7.5 (m, 6H,
Ph), 7.3-7.2 (m, 7H, 3JH-H, m-Ph), 6.7 (d, 2H, 3JH-H = 7 Hz, o-
B(C6F5)3 with 1-hexyne, 3,3-dimethyl-1-butyne, ethynyltri-
methylsilane, and ethynylferrocene afforded the complexes
[tBu3PH][RCCB(C6F5)3] (R = C4H9 2, tBu 3, Me3Si 4, and
CpFe(C5H4) 5), respectively (Scheme 2). Although monitor-
ing of these reactions by NMR spectroscopy indicated that
these small-scale reactions in CD2Cl2 were quantitative with
no formation of addition products, the products 2-5 could
only be isolated in moderate to low yields. These complexes
Ph), 4.2 (d, 2H, 2JH-H = 13 Hz SCH2Ph), 3.9 (d, 2H, 2JH-H
=
13 Hz SCH2Ph). 11B NMR (CD2Cl2): -16.2 (s). 13C{1H} NMR
(255 K, CD2Cl2), partial: 52 mg (88%) 179.1 (m, CdC-B), 147.7
(dm, 1JC-F = 234 Hz, o-C6F5), 138.3 (dm, 1JC-F = 247 Hz, p-
C6F5), 136.4 (dm, 1JC-F = 247 Hz, m-C6F5), 130.2, 129.9, 129.8,
129.6, 129.1, 128.6, 128.3, 126.9, 46.53 (s, CH2Ph). 19F NMR
(CD2Cl2): -131.9 (d, 6F, 3JF-F = 24 Hz, o-C6F5), -161.8 (t, 3F,
3
3JF-F = 21 Hz, p-C6F5), -166.3 (t, 6F, JF-F = 23 Hz, m-
C6F5). Anal. Calcd for C42H20BF15S (852.495): C, 59.18; H,
2.36. Found: C, 59.39; H, 2.40.
(50) Cromer, D. T.; Waber, J. T. Int. Tables X-Ray Crystallogr. 1974,
4, 71–147.
(51) Dureen, M. A.; Stephan, D. W. J. Am. Chem. Soc. 2009, 131,
8396–8397.
X-ray Crystallography. Crystals were coated in Paratone-N
oil in the glovebox, mounted on a MiTegen Micromount, and

Article
Organometallics, Vol. 29, No. 23, 2010 6601
exhibited NMR spectral parameters similar to 1a, and the
structures of 2 and 5 were confirmed by X-ray crystallography
(Figure 1, Table 1). In a similar fashion, FLP deprotonation
of 1,4-diethynylbenzene was employed to prepare the salt
[tBu3PH]2[(C6F5)3BCC(C6H4)CCB(C6F5)3] (6) (Scheme 2).
This species is related to the known salt [Li(THF)4]2-
[Ph3BCC(C6H4)CCBPh3], which draws attention as an “ionic
rotor”.52
Variation in the Lewis acid was probed. We have pre-
viously reported the formation of the aluminum analogue of
1a, [tBu3PH][PhCCAl(C6F5)3] (7, Figure 2, Scheme 2),51
which was readily formed using Al(C6F5)3. In a similar
fashion, the mixed-aryl borane PhB(C6F5)2, despite having
a lower Lewis acidity than B(C6F5)3 (as assessed by Child’s
method:53 0.54 vs 0.68),54 also reacted with PhCCH to afford
the salt [tBu3PH][PhCCBPh(C6F5)2] (8). Even the less Lewis
acidic borane, BPh3, effected the same deprotonation reac-
tion to afford [tBu3PH][PhCCBPh3] (9, Figure 2). In con-
trast, tBu3P BF3 or 1:1 mixtures of tBu3P and BCl3 or tBu3P
3
and B(OC6F5)3 showed no evidence of reaction with
PhCCH. These latter observations suggest that there are
Figure 1. POV-Ray depictions of the anions of (a) 2 and
(b) 5. C: black, Fe: purple, P: orange, F: pink, B: yellow-green.
H atoms are omitted for clarity.
Figure 2. POV-Ray depictions of the anions of (a) 7 and
(b) 9. C: black, P: orange, Al: orchid, F: pink, B: yellow-green.
H atoms are omitted for clarity.
Table 1. Selected NMR Dataa and Metrical Parameters for Deprotonation Products 1-10
11B(29Al) NMR (ppm)
19F NMR Δm-p (ppm)
B(Al)-Csp (A)
Csp-Csp (A)
B(Al)-Csp-Csp (deg)
˚
˚
1c
2
3
4
-20.8
-20.5b
-21.0
-20.8
-20.8
-20.9
103.2
17.13
-12.1
-21.4
3.5
3.0b
3.2
3.4
3.4
3.2
5.9
2.4
1.592(3)
1.592(5)
1.202(3)
1.194(4)
174.7(2)
170.3(3)
5
1.589(2)
1.9478(19)
1.613(2)
1.200(2)
1.207(2)
1.207(2)
166.51(16)
172.51(18)
179.16(18)
6
7c
8
9
10
3.5
a Spectra recorded in CD2Cl2 and reported in ppm. b Spectra recorded in C6D5Br. c Data from ref 51.

6602 Organometallics, Vol. 29, No. 23, 2010
Dureen et al.
Scheme 3. Synthesis of 10
Scheme 4. Generation of 1a and 1b
both a steric and electronic limits for the FLP deprotonation
of terminal alkynes. Similar observations have been ob-
served for the activation of H2 by various FLP mixtures.
The FLP tBu3P and B(C6F5)3 was much less reactive with
internal alkynes. Reactions with 2-hexyne, 3-hexyne, and
2-butyne afforded only inseparable mixtures of products,
whereas combinations with PhCCPh or diphenylbutadiyne
showed no evidence of reaction. These systems stand in
contrast to the reaction of diisopropylbutadiyne with the
linked FLP Mes2PCH2CH2B(C6F5)2 reported by Erker
et al., which yielded an interesting, cyclic phosphonium-
borate cumulene.36 tBu3P and B(C6F5)3 did however react
with an excess of Me3SiCCSiMe3 within minutes to give a
cations as intermediates in the reactions of alkynes with
electrophiles.59,60 A re-examination of the reaction affording
1a at room temperature revealed the formation of a second
minor product (1b) in varying and irreproducible amounts
(5-20%). The latter species was characterized by a doublet
in the 1H NMR spectrum at 8.4 ppm with a JH-P = 27 Hz, an
11B NMR resonance at -16 ppm, and a multiplet in the
31P{1H} NMR spectrum at 44.5 ppm (Table 1). These data
collectively indicate the formation of the zwitterion E-tBu3P-
(Ph)CdC(H)B(C6F5)3 (1b, Scheme 4), presumably formed
via addition of the phosphine and borane to PhCCH. The
latter species could not be isolated from 1a, but the spectro-
scopic similarity to other addition complexes (vide infra)
leaves little doubt of its formulation. In addition, variable-
temperature NMR studies of solutions of initially pure 1a in
C6D5Br revealed partial conversion to 1b at high tempera-
tures (70-130 °C). Cooling such a mixture to room tem-
perature afforded a ca. 19:1 mixture of 1a and 1b. Prolonged
heating of these solutions (ca. 1 week at 80 °C) resulted in no
further enrichment in 1b. Increasing the temperature to 120 °C
(2 h) resulted in partial loss of PhCCH and the liberation of
tBu3P and B(C6F5)3. These data suggest that addition and
deprotonation are reversible and competitive pathways. Thus we
reasoned that FLP-alkyne addition products should be
favored by bulky, less basic phosphines. Indeed, we have
previously communicated that bulky, but less basic phosphines61
such as (o-tol)3P in combination with B(C6F5)3 readily react
with PhCCH to afford the addition complex E-(o-tol)3P-
(Ph)CdC(H)B(C6F5)3 (11) (Scheme 5). In 11, the P and B
centers are trans disposed about the double bond, and the P is
bonded to the substituted carbon of the former alkyne.
In a similar vein, reaction of the Lewis acid-base adduct
1
single product, 10. The H NMR spectrum revealed two
inequivalent Me3Si groups, one of which showed H-P
coupling. The formulation of 10 as the alkynylborate species
[tBu3PSiMe3][Me3SiCCB(C6F5)3] (Scheme 3) is further evi-
denced by a resonance at -21.4 ppm in the 11B NMR
spectrum and was confirmed with preliminary crystallo-
graphic data.55 This silylphosphonium alkynylborate was
highly hygroscopic, and attempts to recrystallize the com-
pound, even in a glovebox atmosphere, led to the isolation of
4, consistent with the sensitivity of the silylphosphonium
cation. However, solutions of 10 in CD2Cl2 sealed in a
Teflon-capped NMR tube were stable for over a week.
Treatment of 10 with additional equivalents of tBu3P and
B(C6F5)3 did not effect cleavage of the Si-C bond of the
silylacetylide fragment of the anion. It is noteworthy that
similar phosphonium cations have been generated via the
treatment of phosphines with Me3SiCo(CO)4.56,57 It is also
of note that base capture of a silylium cation is a critical step
in the proposed mechanism of catalytic hydrosilylation of
imines with B(C6F5)3.58
Phosphine/Borane Addition Reactions with Alkynes. The
mechanism of the deprotonation reactions described above
has not been probed via kinetic study; however it is reason-
able to suggest that alkyne electrophilic attack of the Lewis
acid affords a transient carbocation, which in the presence of
a bulky, basic phosphine such as tBu3P affords the phos-
phonium alkynyl borates (Scheme 4). A competitive reaction
would be addition of the phosphine to the carbocation,
affording a zwitterionic addition product with a trans dis-
position of the P and B centers (Scheme 4). This latter
mechanism is consistent with the common role of vinyl
Ph3P B(C6F5)3 with PhCCH gave the addition complex by
3
the synthesis of E-Ph3P(Ph)CdC(H)B(C6F5)3 (12), while
reaction of Ph3P B(C6F5)3 and ethynylferrocene gave
3
E-Ph3P(CpFe(C5H4))CdC(H)B(C6F5)3 (13, Scheme 5).
The latter species was crystallographically characterized
(Figure 3, Table 2). Reaction of Ph3P B(C6F5)3 with the
(52) Gardinier, J. R.; Pellechia, P. J.; Smith, M. D. J. Am. Chem. Soc.
2005, 127, 12448–12449.
(53) Childs, R. F.; Mulholland, D. L.; Nixon, A. Can. J. Chem. 1982,
60, 801–8.
(54) Morrison, D. J.; Piers, W. E. Org. Lett. 2003, 5, 2857–2860.
(55) Repeated attempts led only to small single crystals of 9, where the
data were not of sufficient quality to merit publication.
(56) Bald, J. F., Jr.; MacDiarmid, A. G. J. Organomet. Chem. 1970,
22, C22–C24.
(57) Schaefer, H.; MacDiarmid, A. G. Inorg. Chem. 1976, 15, 848–
856.
(58) Blackwell, J. M.; Sonmor, E. R.; Scoccitti, T.; Piers, W. E. Org.
3
internal alkyne 1-phenyl-2-propyne, however, did afford
the addition complex E-Ph3P(Ph)CdC(Me)B(C6F5)3 (14),
although higher temperatures were needed to facilitate this
reaction. Similarly to 11, 14 exhibited broadened NMR
resonances due to restricted rotation. Above 100 °C NMR
spectroscopy did not afford the limiting spectra but rather
showed loss of alkyne.
The above syntheses demonstrated that this addition
reactivity is not limited to bulky phosphines that form FLPs
Lett. 2000, 2, 3921–3923.
(59) Patai, S. The Chemistry of the Carbon-Carbon Triple Bond; J.
Wiley: New York, 1978.
(60) Stang, P. J. Vinyl Cations; Academic Press: New York, 1979.
(61) Bush, R. C.; Angelici, R. J. Inorg. Chem. 1988, 27, 681–686.

Article
Organometallics, Vol. 29, No. 23, 2010 6603
with B(C6F5)3. Rather isolable phosphine-borane adducts
provide convenient access to this reactivity, presumable
because of the existence of equilibria affording the FLP. In
this vein, despite the known ability of sterically unencum-
bered phosphines to form classical adducts with B(C6F5)3,
the reaction of the secondary phosphines Ph2PH or
(C6H2Me3)2PH or the primary phosphine (C6H2tBu3)PH2
with B(C6F5)3 and PhCCH afforded the corresponding
addition products E-R2PH(Ph)CdC(H)B(C6F5)3 (R = Ph
15, C6H2Me3 16, and (C6H2tBu3)PH2(Ph)CdC(H)B(C6F5)3
17, Scheme 5, Figure 4).
Variation in the Lewis acid was also possible for these
addition reactions. Treatment of the mixed arylborane PhB-
(C6F5)2 with Ph3P and PhCCH afforded the complex
E-Ph3P(Ph)CdC(H)BPh(C6F5)2 (18), while the analogous
reaction with PhMe Al(C6F5)3 afforded E-Ph3P(Ph)CdC-
3
(H)Al(C6F5)3 (19, Scheme 5). The corresponding combination
of Ph3P and PhMe Al(C6F5)3 with 1-hexyne yielded E-
3
Ph3P(C4H9)CdC(H)Al(C6F5)3 (20), while we also pre-
viously communicated the Al congener of 11, E-(o-tol)3P-
(Ph)CdC(H)Al(C6F5)3 (21) (Scheme 5).51 Whereas the
B-based zwitterionic addition products appeared to be in-
definitely stable, the Al-based zwitterions proved much less
stable and could be stored in the glovebox for no longer than
a few weeks without decomposition.
This reactivity can be extended to provide access to
macrocyclic and chain-like species. For example, the linked
phosphine-borane complex Mes2PC6F4B(C6F5)245 was also
treated with PhCCH to afford the macrocyclic species
[(H)CdC(Ph)Mes2PC6F4B(C6F5)2]2 (22, Scheme 6). The
NMR spectra of this complex showed broadened reso-
nances, and facile loss of PhCCH in solution was observed.
It is unclear whether this fluxionality is due to a rapid
equilibrium, restricted rotation within the molecule, or a
combination of the two. However the complex could be
isolated in moderate yield after treatment with an excess of
PhCCH, and X-ray crystallography verified this formulation
(Figure 5). Alternatively, sequential addition reactions of the
Ph2PCH2CH2PPh2 with PhCCH and B(C6F5)3 was probed.
Indeed, the mono and bis addition products, Ph2PCH2CH2-
PPh2(Ph)CdC(H)B(C6F5)3 (23) and (CH2PPh2(Ph)CdC-
(H)B(C6F5)3)2 (24), respectively (Scheme 6), were observed.
In the case of 23, the 31P{1H} NMR spectrum contains a
Figure 3. POV-Ray depictions of 12. C: black, Fe: purple, P:
orange, F: pink, B: yellow-green. H atoms are omitted for clarity.
Scheme 5. Synthesis of 11-21
3
doublet with a JP-P of 45 Hz attributable to the pendant
phosphine and a complex multiplet attributable to the
phosphonium center, which is coupled to both the pendant
phosphine and the boron center. Complex 24 was not
sufficiently soluble to allow for NMR characterization, but
it could be isolated by crystallization and structurally char-
acterized (Figure 6).
The related addition reaction involving 1,4-diethynylben-
zene and two equivalents of Ph3P B(C6F5)3 afforded only
3
the monoaddition zwitterion E-HCtCC6H4C(PPh3)dC-
(H)B(C6F5)3 (25, Scheme 7), even after several weeks. The
corresponding reaction with one equivalent of Ph3P B-
3
(C6F5)3 afforded 25 in good yield and permitted crystal-
lographic characterization (Figure 7). Given the geometry,
Table 2. Selected NMR Dataa and Bond Lengths of Addition Products 11-21, 32, and 33
11B (29Al) NMR (ppm)
19F NMR Δm-p (ppm)
31P NMR (ppm)
B(Al)-C(dC) (A)
P(S)-C(dC) (A)
˚
˚
˚
CdC (A)
11c
12c
13
14
15
16
17
18
19
20
21c
32
33c
-13.6b
-16.3
-16.3
-13.0
-16.1
-15.6
-16.3
-12.6
115.0
4.0b
4.3
4.3
31.1b
25.2
23.4
16.5
14 4
12.9
-31.1
24.9
23.4
23.0
26.13b
1.642(3)
1.6393(18)
1.638(2)
1.829(2)
1.8056(13)
1.8001(14)
1.346(3)
1.3451(18)
1.348(2)
4.4
4.3
4.4
3.2
6.3
6.5
6.3b
4.6
4.5
1.635(6)
1.641(2)
1.640(2)
1.6350(14)
2.003(2)
1.9984(16)
2.0040(19)
1.640(2)
1.631(4)
1.787(4)
1.350(5)
1.347(2)
1.3445(18)
1.3483(13)
1.349(3)
1.336(2)
1.341(3)
1.333(2)
1.337(4)
1.8139(15)
1.7991(13)
1.8008(10)
1.815(2)
1.8033(15)
1.8199(17)
1.8027(16)
1.798(3)
114.7
116.5b
-16.2
-16.2
a Spectra recorded in CD2Cl2 at 25 °C. b Spectra recorded in C2D2Cl4 at 385 K. c Data from ref 51.

6604 Organometallics, Vol. 29, No. 23, 2010
Dureen et al.
Figure 5. POV-Ray depiction of 22. C: black, P: orange, F:
pink, B: yellow-green. H atoms and cocrystallized solvent
˚
molecules are omitted for clarity. Selected bond lengths (A)
and angles (deg): P-C(dC), 1.859(2); B-C(dC), 1.657(3);
CdC, 1.345(3).
Figure 6. POV-Ray depiction of 24. C: black, P: orange, F:
pink, B: yellow-green. H atoms and cocrystallized solvent
˚
molecules are omitted for clarity. Selected bond lengths (A)
and angles (deg): P-C(dC), 1.790(3); B-C(dC), 1.629(4);
CdC, 1.342(4).
Scheme 6. Synthesis of 22-24
Figure 4. POV-Ray depictions of (a) 15, (b) 16, and (c) 17. C:
black, P: orange, F: pink, B: yellow-green. Most H atoms are
omitted for clarity.
the difficulty with a second addition reaction may be a result
of steric crowding as well as the electron perturbation
resulting from the presence of the zwitterionic unit on
the arene ring. It is interesting, however, that subsequent
treatment of 25 with an additional equivalent of tBu3P
and B(C6F5)3 yielded the unusual salt/zwitterion [tBu3PH]-
[(C6F5)3BCCC6H4C(PPh3)dC(H) B(C6F5)3] (26, Scheme 7).
Nitrogen Base/Borane FLP Reactions with Alkynes. The
corresponding reactions of nitrogen bases, B(C6F5)3, and term-
inalalkynes are not without precedent. Berke and co-workers
reported the deprotonation reactions of alkynes with B-
(C6F5)3 and 2,6-lutidene or 2,2,5,5-tetramethylpiperidine,41
while we have reported the intramolecular addition cycliza-
tion of ortho-ethynylaniline with B(C6F5)3 to give a cyclic
anilinium-borate.62 Interestingly, herein we report the cor-
responding reaction of benzyldimethylamine with PhCCH
(62) Voss, T.; Chen, C.; Kehr, G.; Nauha, E.; Erker, G.; Stephan,
D. W. Chem.;Eur. J. 2010, 16 (3005-3008), S3005/1–S3005/7.

Article
Organometallics, Vol. 29, No. 23, 2010 6605
Figure 8. POV-Ray depiction of 30. C: black, F: pink, N:
aquamarine, B: yellow-green, H: white. Most H atoms and
cocrystallized solvent are omitted for clarity.
Figure 7. POV-Ray depiction of 25. C: black, P: orange, F:
pink, B: yellow-green. Most H atoms and cocrystallized solvent
˚
molecules are omitted for clarity. Selected bond lengths (A) and
angles (deg): P-C(dC), 1.802(3); B-C(dC), 1.641(5); CdC,
1.344(5); CtC, 1.180(7).
Scheme 7. Synthesis of 25 and 26
Scheme 8. Synthesis of 27-29
Figure 9. POV-Ray depiction of (a) 32 and (b) 33. C: black, S:
yellow: F: pink, B: yellow-green. H atoms and cocrystallized
solvent are omitted for clarity.
Scheme 9. Synthesis of 30
Scheme 10. Synthesis of 31-33
and B(C6F5)3, which is shown by NMR spectroscopy to give
a 84:16 mixture of both deprotonation and addition pro-
ducts, [PhCH2NMe2H][PhCCB(C6F5)3] (27a) and PhCH2N-
Me2(Ph)CdC(H)B(C6F5)3 (27b), respectively (Scheme 8).

6606 Organometallics, Vol. 29, No. 23, 2010
Dureen et al.
Table 3. Crystallographic Parametersa
2
5
7
9
13
15
16
formula
C
36H37BF15
P
C42H37BF15FeP
C38H32BF15
1/2C6H5Cl
887.61
monoclinic
P21/c
12.5867(4)
16.6533(5)
19.4595(6)
90
100.5490(10)
90
P
C
38H48BP
C48H25BF15FeP
1/2CH2Cl2
1026.76
monoclinic
P21/n
10.9787(4)
21.7431(7)
17.9889(6)
90
91.597(2)
90
4292.5(3)
4
150(2)
1.587
0.553
71683
0.0445
15 485
628
0.0620
0.2109
1.047
C38H17BF15
1/2CH2Cl2
842.76
triclinic
P1
10.7515(9)
19.2509(18)
19.5755(18)
60.875(5)
84.592(5)
84.082(5)
3516.0(5)
4
150(2)
1.592
0.264
79398
0.0755
11 269
1026
0.0574
P
C44H29BF15
CH2Cl2
969.38
triclinic
P1
12.3010(4)
12.8632(4)
15.2230(5)
74.3200(10)
67.2090(10)
69.473(2)
2054.31(11)
2
150(2)
1.567
0.300
42915
0.0295
11 716
581
0.0438
P
3
3
3
3
fw
cryst syst
space group
796.44
orthorhombic
Pcba
20.0199(10)
16.7127(7)
21.5983(8)
90
90
90
7226.5(5)
8
150(2)
1.462
0.180
35330
0.1112
8286
924.35
triclinic
P1
546.54
monoclinic
P21/c
12.3110(11)
13.8672(13)
19.2209(16)
90
103.184(5)
90
3194.9(5)
4
˚
a (A)
12.1738(9)
12.6282(9)
13.9670(11)
77.682(2)
79.434(2)
73.091(2)
1990.1(3)
2
˚
b (A)
˚
c (A)
R (deg)
β (deg)
γ (deg)
3
˚
V (A )
Z
4010.0(2)
4
T (K)
150(2)
1.543
0.521
150(2)
1.470
0.224
35412
0.0324
9205
150(2)
1.136
0.111
d(calc) gcm-3
μ, mm-1
data collected
Rint
66034
52184
0.0333
9039
674
0.0344
0.0951
1.056
0.0686
7315
374
0.0456
0.1077
1.002
data used
variables
R (>2σ)
wR2
491
554
0.0584
0.1371
0.972
0.0406
0.1079
1.034
0.1746
1.024
0.1290
1.039
GOF
17
18
19
20
22
24
25
27a
29
formula
C44H37BF15P C44H26BF10
1/2CH2Cl2
828.89
P
C44H21AlF15
1/2C6H5Br
971.07
triclinic
P1
11.6961(8)
12.6086(10)
14.700(1)
106.702(3)
100.881(3)
90.595(4)
2034.2(3)
2
150(2)
1.580
0.685
73 453
0.0520
15 379
586
0.0654
P
C
37H21-
AlF15
C
PhMe
1821.04
monoclinic
C2/c
88H56BF28P2
C
78H36B2F30P2 C46H21BF15
P
C35H19
BF15
749.32
monoclinic monoclinic
P21/n C2/c
11.4843(7) 45.9136(16)
13.1053(10) 10.2766(4)
21.4793(15) 32.6110(11)
90
103.838(4) 103.102(2)
90 90
3138.9(4) 14986.5(0)
-
N
C
43H25
BF15
851.45
-
N
3
3
3
3
3
P
2CH2Cl2
898.24
monoclinic
P21/n
12.5795(7)
18.1504(9)
16.3457(9)
90
99.017(4)
90
3686.0(3)
2
150(2)
1.619
0.327
43 972
0.0741
8349
2.5CH2Cl2
1112.72
monoclinic
P21/n
12.1892(8)
18.2218(11)
22.5003(14)
90
103.203(3)
90
4865.4(5)
4
150(2)
1.569
0.424
63 390
0.0399
12 629
649
0.0890
0.2974
1.057
fw
cryst syst
space group
892.52
monoclinic triclinic
872.57
triclinic
P1
9.9634(11) 20.9887(11)
11.2388(13) 20.5295(11)
19.821(2) 18.5092(10)
74.086(6) 90
87.361(5) 96.190(4)
65.541(5) 90
1937.1(4) 7928.9(7)
P21/c
11.6919(8)
P1
10.6158(5)
˚
a (A)
˚
b (A)
17.9236(11) 10.9157(5)
19.8532(11) 18.9691(10)
˚
c (A)
R (deg)
β (deg)
γ (deg)
90
94.709(3)
90
4146.4(5)
4
150(2)
87.183(3)
74.873(2)
65.677(2)
1929.35(16)
2
150(2)
1.416
0.154
90
3
˚
V (A )
Z
T (K)
2
4
4
16
150(2)
1.496
0.197
35 965
0.0378
8848
150(2)
1.517
0.172
66 604
0.0420
9158
150(2)
1.586
0.155
50 804
0.0630
8931
150(2)
1.509
0.140
137 008
0.0457
18 397
1095
0.0518
0.1426
1.016
d(calc) (g cm-3) 1.430
μ (mm-1
data collected 121 123
)
0.166
90 045
0.0338
19 019
532
Rint
0.0414
10 116
567
data used
variables
R (>2σ)
wR2
533
555
532
471
0.0357
0.0965
1.013
0.0461
0.1375
1.017
0.0366
0.1103
1.058
0.0597
0.1742
1.043
0.0547
0.1551
1.023
0.0527
0.1593
1.028
0.2173
1.036
GOF
30
31
32
33
formula
fw
C43H30BN2F15 1/2C6H5Cl
C37H26BF15N2
794.41
monoclinic
P21/c
12.4344(4)
13.5100(4)
24.1219(7)
90
98.576(2)
90
4006.9(2)
4
150(2)
1.343
0.128
35 245
0.0579
9095
C28H12BF15
676.25
monoclinic
P21/c
20.2284(14)
14.5997(10)
18.3315(12)
90
104.952(3)
90
5230.5(6)
8
150(2)
S
C40H20BF15S1/2C6H14
871.52
triclinic
P1
9.9881(3)
11.0871(4)
17.1835(6)
82.846(2)
74.407(2)
85.779(2)
1816.98(11)
2
150(2)
1.558
0.199
26 701
0.0518
7604
526
0.0532
3
926.27
triclinic
P1
cryst syst
space group
˚
a (A)
11.2560(7)
12.2232(8)
16.5685(11)
104.065(4)
107.259(4)
90.364(4)
2104.1(2)
2
150(2)
1.462
0.162
34 343
0.0459
9768
˚
b (A)
˚
c (A)
R (deg)
β (deg)
γ (deg)
3
˚
V (A )
Z
T (K)
d(calc) (g cm-3
)
1.718
0.251
148 855
0.0627
12 866
abs coeff, μ (mm-1
data collected
Rint
)
data used
variables
R (>2σ)
wR2
GOF
592
502
815
0.0901
0.2830
1.081
0.0659
0.2033
1.154
0.0352
0.0851
1.012
0.1445
1.015
a
˚
Data collected Mo KR radiation (λ = 0.71073 A).

Article
Organometallics, Vol. 29, No. 23, 2010 6607
Although these species give rise to the characteristic 11B
NMR resonances at -20.8 and -16.4 ppm, respectively,
only the former could be isolated and fully characterized.
The structure of 27a was confirmed crystallographically. In a
similar fashion, the imines tBuNdCHPh and tBuNdCPh2
react quantitatively with PhCCH and B(C6F5)3 to afford the
iminium-alkynylborate salts [(tBu)HNdCHPh][PhCCB(C6F5)3]
(28) and [(tBu)HNdCPh2][PhCCB(C6F5)3] (29), respectively
(Scheme 8). Spectral parameters were as expected, and the
structure of 29 was unambiguously confirmed by crystal-
lographic methods. Transformation of 28 and 29 to the
borane adducts of the corresponding propargylamines via
thermolytic phenylacetylide transfer from boron to the
activated iminium cation was explored. Although 11B
NMR and 19F NMR spectra were consistent with acetylide
transfer to the iminium cation, efforts to isolate these species
were unsuccessful.
In a final example of a nitrogen base reaction, tBuNCNt-
Bu, B(C6F5)3, and two equivalents of PhCCH were com-
bined. This resulted in several products; however the major
product (30, Scheme 9) was isolated as a crystalline solid in
64% yield. The nature of this species was confirmed crystal-
lographically (Figure 8), and it was consistent with concur-
rent addition and deprotonation reactions. The product 30,
formulated as [tBuNCN(H)C(Ph)dC(H)tBu][PhCCB(C6F5)3],
appears to result from both deprotonation and addition
reactions with PhCCH, although the order of reaction
remains unclear. One possible sequence involves deprotona-
tion of PhCCH and addition of the resulting iminium to a
second equivalent of alkyne with proton and tBu group
migration (Scheme 9). This unusual reaction was reproduci-
ble, although this reactivity could not be extended to other
carbodiimides.
structure of 32 was determined (Figure 9), revealing a S-Csp2
˚
bond length of 1.8027(16) A and CdC and B-Csp2 bond
lengths similar to those of the phosphine addition complexes
(vide supra). The corresponding reaction with (PhCH2)2S
was also probed. This sulfide and B(C6F5)3 form a weak
adduct in CD2Cl2, as evidenced by a broad resonance in the
11B NMR spectrum at 0.5 ppm, and consequently this
adduct was not isolated. Thus combination of B(C6F5)3,
PhCCH, and excess (PhCH2)2S afforded the sulfonium-
borate zwitterion E-(PhCH2)2S(Ph)CdC(H)B(C6F5)3 (33,
Scheme 10) in moderate yield. This species was stable for
at least one hour in CD2Cl2 at -30 °C, but at room
temperature the reaction was readily reversible, ultimately
yielding the vinyl-boranes that are derived from reaction of
PhCCH and B(C6F5)3 alone. The species 33 was also char-
acterized by X-ray diffraction studies (Figure 9) and exhib-
ited metrical parameters similar to 32. The reversibility of the
formation of these sulfonium salts may be exploited. Addi-
tion of one equivalent of Ph3P to 33 resulted in the initial
precipitation of the adduct Ph3P B(C6F5)3, which upon
3
standing for 24 h gave quantitative conversion to 12. In a
related sense, addition of tBu3P afforded a mixture of 1a and
1b. It is also noteworthy that related sulfonium-borate
zwitterions are thought to be intermediates in the homologa-
tion reactions of boranes via the alkylation of organoborane-
thioethers with iodomethane.64 In the latter case however,
the salts contain a single C atom between S and B and were
not isolable.
Conclusions. The reactions of FLPs with terminal alkynes
afford either phosphonium-alkynylborate salts, resulting
from deprotonation of the alkyne, or zwitterions, resulting
from addition of both the Lewis acid and base. In addition,
despite the formation of classical Lewis adducts by some
donors, this FLP reactivity is still accessible. Indeed, the
range of Lewis bases that participate in this reactivity was
expanded to include secondary and primary phosphines,
carbenes, and thioethers. Similarly the range of Lewis acids
was broadened to include Al(C6F5)3, PhBP(C6F5)2, and
B(C6F5)3. In general the products were found to be quite
stable, although in several cases the addition reactions were
demonstrated to be reversible. In addition, we have observed
the first Si-C cleavage effected by an FLP and the first FLP
with a S-based nucleophile.
Non-pnictogen Lewis Bases and FLP Reactions with Al-
kynes. It has been previously demonstrated that N-hetero-
cyclic carbenes (NHCs) can be used as the Lewis base in an
FLP to effect both H-H and N-H bond cleavage.22,63 Thus,
B(C6F5)3 was added to a mixture of 1,3-di-tert-butylimida-
zolin-2-ylidene and PhCCH at -78 °C, resulting in the facile
formation of the corresponding deprotonation product
[(tBuN)2C3H3][PhCCB(C6F5)3] (31, Scheme 10), as evi-
denced by spectroscopic data. This thermally stable product
was also characterized by X-ray crystallography. The for-
mation of this deprotonation product is consistent with the
strong Bronsted basicity of the carbene.
The reactivity of the products is a subject of continuing
interest. In particular, we are exploring the utility of the
products of primary and secondary phosphine reactions, as
these species offer unique routes to anionic phosphines. We are
also pursuing the utility of this reactivity in developing reagents
for further use in subsequent organic transformations.
Sulfides are generally considered to be both poor Bronsted
and Lewis bases and, in that sense, at the opposite end of the
spectrum of donor ligands from carbenes. Nonetheless, they
do form adducts with the strongly electrophilic B(C6F5)3.
Addition of PhCCH to a solution of Me2S B(C6F5)3 af-
3
forded the zwitterion E-Me2S(Ph)CdC(H)B(C6F5)3 (32,
Scheme 10). Although solutions of 32 in CD2Cl2 were
initially spectroscopically clean, after 30 min at room tem-
Acknowledgment. Financial support of NSERC of
Canada is gratefully acknowledged. D.W.S. is grateful
for the award of a Canada Research Chair and a Killam
Research Fellowship for 2009-2011.
perature formation of some Me2S B(C6F5)3 and the pro-
3
ducts of the reaction of B(C6F5)3 and PhCCH were observed
in solution, illustrating that this reaction was reversible at
room temperature. Nonetheless, the solid-state molecular
Supporting Information Available: This material is available
free of charge via the Internet at http://pubs.acs.org.
(63) Holschumacher, D.; Bannenberg, T.; Hrib, C. G.; Jones, P. G.;
Tamm, M. Angew. Chem., Int. Ed. 2008, 47, 7428–7432.
(64) Negishi, E.-i.; Yoshida, T.; Silveira, A.; Chiou, B. L. J. Org.
Chem. 1975, 40, 814–816.