C-lithiation/alkylation of trimethylamine cyanoborane

Article abstract of DOI:10.1021/om049816p

C-lithiation of trimethylamine cyanoborane readily occurs with 1.5 equiv of s-BuLi. The C-lithiated complex 1 reacts with various electrophiles such as alkyl iodides, aldehydes, ketones, allyl bromide, and bromot-rimethylsilane to give the corresponding p

Full text of DOI:10.1021/om049816p

Organometallics 2004, 23, 2817-2820
2817
C-Lith ia tion /Alk yla tion of Tr im eth yla m in e Cya n obor a n e
Khuloud Takrouri, J ehoshua Katzhendler, and Morris Srebnik*
Department of Natural Products and Medicinal Chemistry, School of Pharmacy,
Hebrew University in J erusalem, J erusalem 91120, Israel
Received March 14, 2004
Summary: C-lithiation of trimethylamine cyanoborane
readily occurs with 1.5 equiv of s-BuLi. The C-lithiated
complex 1 reacts with various electrophiles such as alkyl
iodides, aldehydes, ketones, allyl bromide, and bromot-
rimethylsilane to give the corresponding products 2-14,
in excellent conversion and in good yields. This is the
first example of C-lithiation/ alkylation of an amine
cyanoborane and allows the preparation of amine cy-
anoboranes not readily available before.
occurs on C1 and not on C4 as in the uncomplexed
case.13 Thus, interesting differences in reactivity can be
anticipated between complexed and uncomplexed amines.
C-lithiation of amine cyanoboranes would offer a new
route to more complex amine cyanoboranes not readily
attainable by other methods.
Resu lts a n d Discu ssion
C-lith ia tion of Tr im eth yla m in e Cya n obor a n e
a n d R ea ct ion w it h Alk yl H a lid es. C-lithiated tri-
methylamine cyanoborane, Li+[CH2N(Me)2BH2CN]- (1)-
, was obtained in situ from trimethylamine cyanoborane,
Me3NBH2CN, using 1.5 equiv of s-BuLi as the depro-
tonation reagent. n-BuLi was less effective.14,16,17 Meta-
lation using 1.5 equiv of s-BuLi in THF at -78 to +25
°C, recooling the reaction to -78 °C, adding the elec-
trophile, and warming the reaction mixture to 25 °C
gave the highest yields. Metalation at -78 °C gave back
only starting material. The use of fewer than 1.5 equiv
resulted in reduced conversion to product. Raising the
amount of s-BuLi to 3 equiv did not increase the yield,
except in the case of MeI. The need to use an ap-
proximately 50% excess of s-BuLi reagent may be due
to the known instability of organolithium reagents in
THF.18 Adventitious water may also be involved.17 The
reaction proceeds with alkyl iodides, allyl bromide, and
bromotrimethylsilane to provide compounds 2-6 (Scheme
1, Table 1). The desired compounds were obtained with
excellent conversion. Attempted purification of the
amine cyanoboranes on silica resulted in decomposition.
However, after extensive investigation, products 2-6
could be separated from the starting material by
multiple extractions in benzene/water, where Me3NBH2-
CN has higher solubility in water. Using this selective
extraction technique, products 2-6 were obtained in
high purity. However, this caused a partial decrease in
the isolated yield, mainly of 2, due to loss of the product
in the aqueous layer (Table 1).
In tr od u ction
Amine cyanoboranes are interesting compounds that
were first reported in 1970.1 In 1974 Bratt reported the
preparation of amine cyanoboranes by the reaction of
cyanide and amine iodoboranes.2 Reaction of NaBH3-
CN with X2 and conversion of the oligomer with amines
was reported in 1978 by Martin.3 In the same year,
Spielvogel4 developed a general method for the synthesis
of amine-cyanoboranes based on amine boranes5 and
NaBH3CN. In 1984 Geanangel prepared a quinuclidine
derivative by amine exchange.6 In 1990 Todd devised a
protocol for synthesizing amine alkyl cyanoboranes from
alkyl trihydroborates and mercuric cyanide.7 Gyo¨ri has
reported the use of oligomeric NaBH3CN in the presence
of SMe2.8 More recently, he reported the synthesis of
amine dicyanoboranes.9 Amine cyanoboranes can be
converted to amine carboxyboranes, isoelectronic ana-
logues of amino acids.10 Both amine carboxyboranes and
amine cyanoboranes have been shown to possess con-
siderable biological activity.10,11
Amine boranes and other Lewis acid complexed
boranes can be C-lithiated.12-17 In the case of tetrahy-
droisoquinolines, C-lithiation of the complexed amine
* To whom correspondence should be addressed. E-mail: msrebni@
md.huji.ac.il.
(1) Uppal, S. S.; Kelly, H. C. Chem. Commun. 1970, 1619.
(2) Bratt, P. J .; Brown, M. P.; Seddon, K. R. J . Chem. Soc., Dalton
Trans. 1974, 2161-2163.
(3) (a) Martin, D. R.; Chiusano, M. A.; Denniston, M. L.; Dye, D. J .;
Martin, E. D.; Pennington, B. T. J . Inorg. Nucl. Chem. 1978, 40, 9-13.
For numerous examples see: (b) Mittakanti, M.; Charandabi, M. R.
M. D.; Morse, K. W. Inorg. Chem. 1990, 29, 3218-3220. (c) Sutton, C.
H.; Baize, M. W.; Todd, L. J . Inorg. Chem. 1994, 33, 4221-4225.
(4) Wisian-Neilson, P.; Das, M. K.; Spielvogel, B. F. Inorg. Chem.
1978, 17, 2327-2329.
Rea ction of th e C-lith ia ted Tr im eth yla m in e Cy-
a n obor a n e w ith Keton es a n d Ald eh yd es. The same
(12) Spielvogel, B. F. Phosphorus, Sulfur Silicon Relat. Elem. 1994,
87, 267-276.
(13) Dembitsky, V. M.; Srebnik, M. Tetrahedron 2003, 59, 579-593.
(14) Kessar, S. V.; Singh, P. Chem. Rev. 1997, 97, 721-737.
(15) Kessar, S. V.; Singh, P.; Vohra, R.; Kaur, N. P.; Singh, K. N.
Chem. Commun. 1991, 568-570.
(16) Ebden, M. R.; Simkins, S. N. Tetrahedron Lett. 1995, 36, 8697-
8700.
(17) Ebden, M. R.; Simkins, S. N.; Fox, D. N. A. Tetrahedron 1998,
54, 12923-12952.
(5) Schaefer, G. W.; Anderson, E. R. J . Am. Chem. Soc. 1949, 71,
2137-2143.
(6) Kemp, B.; Kalbag, S.; Geanangel, R. A. Inorg. Chem. 1984, 23,
3063-3065.
(7) Mills, W. J .; Sutton, C. H.; Libby, E.; Todd, L. J . Inorg. Chem.
1990, 29, 302-308.
(8) Gyori, B.; Lazar, I.; Emri, J . J . Organomet. Chem. 1988, 344,
29-35.
(9) Berente, Z.; Gyori, B. Inorg. Chem. 1999, 38, 5250-5256.
(10) Spielvogel, B. F.; Das, M. K.; McPhail, A. T.; Onan, K. D.; Hall,
I. H. J . Am. Chem. Soc. 1980, 102, 6343-6344.
(11) Hasan, A.; Li, H.; Tomasz, J .; Shaw, B. R. Nucleic Acids Res.
1996, 24, 2150-2157.
(18) (a) Gilman, H.; Gaj, B. J . Org. Chem. 1957, 22, 1165-1168. (b)
Rembaum, A.; Siao, S. P.; Indictor, N. J . Polym. Sci. 1962, 56, S17-
S19. (c) Honeycutt, S. C. J . Organomet. Chem. 1971, 29, 1-5. (d) Bates,
R. B.; Kroposki, L. M.; Potter, D. E. J . Org. Chem. 1972, 37, 560-565.
(e) Maercker, A. Angew. Chem., Int. Ed. Engl. 1987, 26, 972-989.
10.1021/om049816p CCC: $27.50 © 2004 American Chemical Society
Publication on Web 04/24/2004

2818 Organometallics, Vol. 23, No. 11, 2004
Notes
attributed to the â-effect of the CH2SiMe3 group,22 which
may reduce the charge density localized on the boron
atom. In addition to the appearance of the signals
Sch em e 1. Syn th esis of Am in e Cya n obor a n es
2-14 fr om Tr im eth yla m in e Cya n obor a n e
1
attributable to the N-CH2R group in the H and 13C
NMR spectra for compounds 7-14, a peak due to H-C-
OH with the expected multiplicity appeared downfield
1
between 4.2 and 6.5 ppm in the H NMR spectra, and
between 68 and 71 ppm in 13C NMR spectra. This is
expected due to the deshielding effect of the two
adjacent electron-withdrawing groups (hydroxyl and
amine groups). The methylene hydrogens (N-CH2CH-
(OH)R) of complexes 8-14 are now diastereotopic and
in most cases showed different peaks for each hydrogen.
The N-methyl groups (NMe2) are also diastereotopic,
1
and peaks for each group were evident in both the H
and 13C NMR spectra (see Experimental Section). In the
11B NMR spectra, comparison of the chemical shifts
reveals a downfield shift of approximately 2 ppm in
compounds 7-14 compared to compounds 2-6. This is
attributed to the presence of the OH group, which
reduces the charge density on the boron atom. B-H
(2894-2939 cm-1), CtN (2337-2361 cm-1), and B-N
(428-461 cm-1) bands in the IR spectra were present
in all compounds and are consistent with the assigned
structures. In the hydroxyl-containing compounds 7-14,
broad bands due to O-H also appeared in the range of
Ta ble 1. Am in e Cya n obor a n es 2-14 P r ep a r ed
fr om Me3NBH2CN
compd
R
R′
X
yield (%)a
2
3
4
5
6
7
8
9
10
11
12
13
14
Me
n-Pr
n-Bu
allyl
Me3Si
Me
Me
I
I
I
Br
Cl
80
86
84
87
94
83
85
88
87
87
84
87
85
Me
H
H
H
H
H
H
H
Ph
anisyl
styryl
furan-2-yl
p-tolyl
o-tolyl
3367-3422 cm-1
.
Particularly interesting were the mass spectra re-
sults. For LC-MS spectra, compounds 7-14 were dis-
solved in water; it was evident that they have a high
affinity for complexation with water and form a number
of water complexes. All mass spectra of 7-14 showed a
molecular peak of (M + 2n) × 18. Fragmentation peaks
due to successive loss of molecules of water were also
prominent. In addition, a peak at M - 18 also appeared
for 7-14, due to water loss (eq 1).
a
Isolated yield.
reaction conditions were then used with different ke-
tones and aldehydes such as acetone, acetaldehyde,
benzaldehyde, cinnamaldehyde, furaldehyde, anisalde-
hyde, p-tolualdehyde, and o-tolualdehyde, to give the
hydroxyl-containing amine cyanoboranes 7-14 (Scheme
1). The excesses of nonvolatile or non-water-soluble
aldehydes were removed from the crude product using
concentrated aqueous sodium bisulfite solution, to give
the so-called sodium bisulfite addition compounds,
which produced a precipitate that was separated by
filtration.19 For compounds 7-14, unreacted Me3NBH2-
CN was removed by several extractions in CH2Cl2/
water. Compounds 7-14 were obtained in good isolated
yields and in high purity (Scheme 1, Table 1).
Con clu sion
A series of alkylamine cyanoboranes and hydroxyl-
containing amine cyanoboranes were prepared by a
simple method involving C-lithiation of trimethylamine
cyanoborane with s-BuLi, to produce 1. Subsequent
reactions with alkyl halides gave compounds 2-6 in
high purity and yield. Reaction of 1 with aldehydes and
ketones provided 7-14. Many of these compounds were
not previously available or could only be synthesized in
multiple steps and low yields.
Sp ectr oscop ic An a lysis. Compounds 2-14 were
1
fully characterized by H, 13C, and 11B NMR, GC/MS,
1
LC/MS, FT-IR and elemental analysis. The H and 13C
NMR spectra for compounds 2-6 contain new peaks due
to the N-CH2R group with the expected multiplicity in
1
the H NMR: a triplet for 2, doublets for 3-5, and a
singlet for 6. In the 13C NMR spectra of all compounds,
no peaks due to cyano carbon atoms were found, due to
the rapid relaxation of the boron-bonding carbon.20 In
all cases, negative boron chemical shifts were observed
which are typically associated with tetracoordinate
boron. An upfield shift of the 11B resonances is expected,
due to the significant donation from the nitrogen atom
into the vacant p orbital on the boron.21 In view of this,
the downfield shift of compound 6 can possibly be
Exp er im en ta l Section
1
Gen er a l Com m en ts. H, 13C, and 11B NMR spectra were
recorded in CDCl3 solution on a Varian Unity spectrometer
(300, 75, 96 MHz) using Me4Si as an internal standard for 1H
and 13C NMR and Et2O‚BF3 as an external standard for 11B
NMR. Infrared spectra were run for samples as neat films for
liquids and in KBr disks for solids on a Bruker Vector 22 FT-
(21) Irvine, G. J .; Gerald Lesley, M. J .; Marder, T. B, Norman, N.
C.; Rice, C. R.; Robins, E. G.; Roper, W. R.; Whittell, G. R.; Wright, L.
J . Chem. Rev. 1998, 98, 2685-2722.
(22) No¨th, H.; Wrackmeyer, B, Nuclear Magnetic Rresonance of
Boron Compounds; Springer-Verlag: Berlin, Heidelberg, Germany,
1978; p 35.
(19) Hazzard, B. J . Organicum: Practical Handbook of Organic
Chemistry; Pergamon Press: Oxford, U.K., 1973; p 417.
(20) Das, M, K.; Bandyopadhyay. Inorg. Chem. 1994, 33, 5358-5359.

Notes
Organometallics, Vol. 23, No. 11, 2004 2819
IR spectrophotometer. GC-MS analyses were performed on an
HP GCMS instrument (Model HP6890 GC /HP5971 MSD) with
an electron impact detector and 30 m methyl silicon column.
LC-MS analyses were performed on a Finnigan LCQDUO
Thermo Quad, with electron spray detector. Elemental analy-
ses were performed in house at the Hebrew University
Microaanalysis laboratory. Melting points were measured on
a Fisher Scientific melting point apparatus.
(87), 56 (61), 55 (25), 54 (7), 52 (7). Anal. Calcd for C8H19BN2:
C, 62.37; H, 12.43; N, 18.18. Found: C, 62.06; H, 12.19; N,
19.14.
Bu t-3-en yld im eth yla m in e Cya n obor a n e (5). Yellow oil,
1
87% (0.12 g) yield. H NMR (CDCl3): δ 2.46 (m, 2H), 2.66 (s,
6H), 2.91 (t, 2H, J ) 7.2 Hz), 5.13 (m, 2H), 5.69 (m, 1H); BH
cannot be detected. 13C{1H} NMR (CDCl3): δ 23.21, 50.30,
62.74, 118.54, 133.11; CB cannot be detected. 11B NMR
(CDCl3): δ -15.87 (t, J B-H ) 104.5 Hz). IR (neat, cm-1): 2909
(B-H), 2360 (CtN), 1645 (CdC), 1470 (C-N), 443 (B-N). MS
(EI): m/z (%) 138 (M+, 1), 137 (15), 110 (25), 96 (23), 84 (15),
83 (58), 69 (8), 58 (100), 56 (58), 55 (58), 54 (60), 53 (15), 52
(10), 51 (7). Anal. Calcd for C7H15BN2: C, 60.92; H, 10.95; N,
20.30. Found: C, 60.61; H, 10.73; N, 21.40.
Me3NBH2CN was prepared from Me3N‚HCl and NaBH3CN
using the literature method.4 All reactions were carried out
under a dry nitrogen atmosphere. Solvents were dried by the
usual methods and distilled before use. All other chemicals
were obtained from Sigma-Aldrich and used as received
without any further purification.
Dim eth yl((tr im eth ylsilyl)m eth yl)a m in e Cya n obor a n e
(6). Yellow oil, 94% (0.16 g) yield. 1H NMR (CDCl3): δ 0.21 (s,
9H), 2.58 (s, 2H), 2.74 (s, 6H); BH cannot be detected. 13C-
{1H} NMR (CDCl3): δ 0.05, 54.58, 58.46; CB cannot be
detected. 11B NMR (CDCl3): δ -14.94 (t, J B-H ) 100.9 Hz). IR
(neat, cm-1): 2917 (B-H), 2337 (CtN), 1466 (C-N), 446 (B-
N). MS (EI): m/z (%) 170 (M+, 17), 169 (7), 155 (10), 142 (17),
131 (13), 116 (58), 101 (17), 87 (17), 83 (12), 73 (25), 70 (20),
58 (100), 56 (17). Anal. Calcd for C7H19BN2Si: C, 49.42; H,
11.26; N, 16.47. Found: C, 49.17; H, 11.04; N, 17.34.
Dim eth yl(2-m eth yl-2-h ydr oxypr opyl)am in e Cyan obor -
a n e (7). Yellow oil, 83% (0.13 g) yield. 1H NMR (CDCl3): δ
1.38 (s, 6H), 2.88 (s, 6H), 3.00 (s, 2H); BH cannot be detected.
13C{1H} NMR (CDCl3): δ 30.83, 50.50, 61.89, 69.35; BC cannot
be detected. 11B NMR (CDCl3): δ -13.55 (t, J B-H ) 106.2 Hz).
IR (neat, cm-1): 3422 (O-H), 2939 (B-H), 2361 (CtN), 1467
(C-N), 433 (B-N). MS (ES): m/z (%) 157 (M + 1, 35), 138
(10), 179 (20), 174 (94), 192 (15), 228 (18), 264 (90), 300 (95).
Anal. Calcd for C7H17BN2O: C, 53.88; H, 10.98; N, 17.95.
Found: C, 53.61; H, 10.76; N, 17.59.
Gen er a l P r oced u r e.4 A 0.098 g (1 mmol) amount of Me3-
NBH2CN (1) was dissolved in 10 mL of dry THF, the solution
was cooled to -78 °C, and 1.15 mL (1.5 mmol) of 1.3 M s-BuLi/
cyclohexane solution was added dropwise. The reaction mix-
ture was warmed gradually to room temperature over a period
of 1 h and then recooled to -78 °C, and 1.5 mmol of the
appropriate electrophile was added in one portion. After 5 min
the cooling bath was removed, and the reaction mixture was
stirred for 0.5 h. Then 10 mL of saturated aqueous NaHCO3
solution was added to the reaction mixture. The organic layer
was separated, washed with brine, dried over sodium sulfate,
filtered, and concentrated under vacuum. A yellowish liquid,
which contains the desired product, in addition to the unre-
acted starting materials was obtained.
P u r ifica tion . Crude 2-6 were dissolved in 5 mL of benzene
and washed with distilled water (7 × 5 mL). The benzene layer
was dried over sodium sulfate, filtered, and concentrated under
vacuum. Crude 7-14 were dissolved in 5 mL of ether, and
these solutions were stirred for 3 h with 10 mL of saturated
aqueous sodium bisulfite solution. The precipitate was filtered
out and discarded. The ether layer was dried over sodium
sulfate, filtered, and concentrated under vacuum.19 The crude
product was then dissolved in 5 mL of CH2Cl2, and this
solution was washed with distilled water (7 × 5 mL). The
organic layer was extracted, dried over sodium sulfate, filtered,
and concentrated under vacuum.
Dim eth yl(2-h yd r oxyp r op yl)a m in e Cya n obor a n e (8).
1
Red oil, 85% (0.12 g) yield. H NMR (CDCl3): δ 1.23 (d, 3H, J
) 6.3 Hz), 2.87 (s, 3H), 2.75 (s, 3H), 2.87 (d, 1H, J ) 12.9 Hz),
2.88 (d, 1H, J ) 7.2 Hz), 4.40 (m, 1H); BH cannot be detected.
13C{1H} NMR (CDCl3): δ 23.21, 49.41, 52.57, 63.49, 69.25; CB
cannot be detected. 11B NMR (CDCl3): δ -10.56 (t, J B-H
)
91.1 Hz). IR (neat, cm-1): 3365 (O-H), 2917 (B-H), 2359 (Ct
N), 1456 (C-N), 433 (B-N). MS (ES): m/z (%) 143 (M + 1,
74), 124 (6), 165 (22), 178 (50), 214 (100), 286 (64). Anal. Calcd
for C6H15BN2O: C, 50.75; H, 10.65; N, 19.73. Found: C, 50.34;
H, 10.44; N, 19.34.
Eth yld im eth yla m in e Cya n obor a n e (2). Yellow oil, 80%
(0.09 g) yield. 1H NMR (CDCl3): δ 1.28 (t, 3H, J ) 7.2 Hz),
2.63 (s, 6H), 2.99 (q, 2H, J ) 7.2 Hz); HB cannot be
detected.13C{1H} NMR (CDCl3): δ 9.05, 49.41, 58.21; CB
cannot be detected. 11B NMR (CDCl3): δ -15.98 (t, J B-H
)
Dim eth yl(2-p h en yl-2-h yd r oxyeth yl)a m in e Cya n obor -
102.6 Hz). IR (neat, cm-1): 2894 (B-H), 2361 (CtN), 1459
(C-N), 430 (B-N). MS (EI): m/z (%) 112 (M+, 1), 111 (15), 84
(25), 83 (100), 73 (14), 58 (100), 43 (8), 29 (20). Anal. Calcd for
C5H13BN2: C, 53.63; H, 11.70; N, 25.02. Found: C, 53.36; H,
11.47; N, 23.83.
1
a n e (9). Yield 88% (0.18 g), mp 119 °C. H NMR (CDCl3): δ
2.82 (s, 3H), 2.88 (s, 3H), 3.04 (d, 1H, J ) 3.9 Hz), 3.05 (d, 1H,
J ) 7.5 Hz), 5.38 (dd, 1H, J ) 4.2, 4.2 Hz), 7.39 (m, 5H); BH
cannot be detected. 13C{1H} NMR (CDCl3): δ 50.07, 53.36,
69.61, 70.53, 125.99, 128.86, 129.22, 141.60; BC cannot be
detected. 11B NMR (CDCl3): δ -13.62 (t, J B-H ) 104.5 Hz). IR
(KBr, cm-1): 3374 (O-H), 2894 (B-H), 2360 (CtN), 1462 (C-
N), 430 (B-N). MS (ES): m/z (%) 205 (M + 1, 65), 227 (29),
222 (10), 276 (40), 348 (100). Anal. Calcd for C11H17BN2O: C,
64.74; H, 8.40; N, 13.73. Found: C, 64.22; H, 8.38; N, 14.45.
Dim et h yl(2-(4-m et h oxyp h en yl)-2-h yd r oxyet h yl)a m -
in e Cya n obor a n e (10). Yellow oil, 87% (0.20 g) yield. 1H
NMR (CDCl3): 2.80 (s, 3H), 2.85 (s, 3H), 3.02 (d, 2H, J ) 6.0
Hz), 4.59 (s, 3H), 5.30 (t, 1H, J ) 6.0 Hz), 6.87 (d, 1H, J ) 1.5
Hz), 6.89 (d, 1H, J ) 2.1 Hz), 7.26 (d, 1H, J ) 3.3 Hz), 7.29 (d,
1H, J ) 2.4 Hz); BH cannot be detected. 13C{1H} NMR
(CDCl3): δ 29.93, 49.94, 53.24, 69.58, 70.04, 114.15, 114.50,
127.28, 128.91; BC cannot be detected. 11B NMR (CDCl3): δ
-13.20 (t, J B-H ) 104.5 Hz). IR (neat, cm-1): 3378 (O-H), 2902
(B-H), 2360 (CtN), 1461 (C-N), 444 (B-N). MS (ES): m/z
(%) 235 (M + 1, 5), 216 (35), 257 (45), 252 (5), 270 (8), 306
(100), 342 (40), 378 (6). Anal. Calcd for C12H19BN2O2: C, 61.57;
H, 8.18; N, 11.97. Found: C, 61.26; H, 8.01; N, 14.31.
n -Bu tyld im eth yla m in e Cya n obor a n e (3). Yellow oil,
86% (0.12 g) yield. 1H NMR (CDCl3): δ 0.84 (t, 3H, J ) 7.2
Hz), 1.22 (sex, 2H, J ) 7.2 Hz), 1.54 (m, 2H), 2.52 (s, 6H), 2.73
(t, 2H, J ) 7.2 Hz); HB cannot be detected. 13C{1H} NMR
(CDCl3): δ 13.86, 20.31, 25.40, 49.99, 63.45; CB cannot be
detected. 11B NMR (CDCl3): δ -15.98 (t, J B-H ) 104.4 Hz). IR
(neat, cm-1): 2894 (B-H), 2360 (CtN), 1464 (C-N), 430 (B-
N). MS (EI): m/z (%) 140 (M+, 10), 139 (15), 137 (15), 112 (20),
101 (12), 86 (10), 83 (100), 82 (30), 81 (15), 71 (5), 58 (100), 57
(22), 56 (75). Anal. Calcd for C7H17BN2: C, 60.04; H, 12.24; N,
20.00. Found: C, 59.74; H, 11.99; N, 19.05.
Dim eth yl-n -p en tyla m in e Cya n obor a n e (4). Yellow oil,
84% (0.14 g) yield. 1H NMR (CDCl3): δ 0.82 (t, 3H, J ) 7.5
Hz), 1.23 (m, 4H), 1.59 (m, 2H), 2.55 (s, 6H), 2.76 (t, 2H, J )
7.2 Hz); HB cannot be detected. 13C{1H} NMR (CDCl3):
δ
14.04, 22.43, 23.09, 29.12, 50.01, 63.687; CB cannot be
detected. 11B NMR (CDCl3): δ -15.93 (t, J B-H ) 104.4 Hz). IR
(neat, cm-1): 2894 (B-H), 2360 (CtN), 1459 (C-N), 449 (B-
N). MS (EI): m/z (%) 154 (M+, 1), 153 (10), 151 (20), 126 (27),
115 (12), 98 (7), 85 (2), 83 (100), 82 (36), 71 (6), 70 (11), 58
Dim et h yl(4-p h en yl-2-h yd r oxyb u t -3-en yl)a m in e Cy-
a n ob or a n e (11). Yellow oil, 87% (0.02 g) yield. 1H NMR

2820 Organometallics, Vol. 23, No. 11, 2004
Notes
(CDCl3): δ 2.71 (s, 3H), 2.82 (s, 3H), 2.97 (d, 1H, J ) 9.3 Hz),
3.05 (d, 1H, J ) 2.1), 6.14 (dd, 1H, J ) 6.6, 6.6 Hz), 6.37 (dt,
1H, J ) 5.7, 6.6 Hz), 6.71 (d, 1H, J ) 15.9 Hz), 7.25 (m, 5H);
BH cannot be detected. 13C{1H} NMR (CDCl3): δ 29.95, 49.95,
63.96, 67.68, 68.95, 126.70, 126.90, 128.83, 128.98; CB cannot
be detected. 11B NMR (CDCl3): δ -13.13 (t, J B-H ) 100.8 Hz).
IR (neat, cm-1): 3382 (O-H), 2917 (B-H), 2360 (CtN), 1455
(C-N), 427 (B-N). MS (ES): m/z (%) 231 (M + 1, 15), 212
(12), 253 (43), 302 (100), 338 (6). Anal. Calcd for C13H19BN2O:
C, 67.85; H, 8.32; N, 12.17. Found: C, 67.58; H, 8.29; N, 11.93.
(2-(F u r a n -2-yl)-2-h yd r oxyeth yl)d im eth yla m in e Cya n o-
b or a n e (12). Orange oil, 84% (0.16 g) yield. 1H NMR
(CDCl3): δ 2.67 (s, 3H), 2.77 (s, 3H), 3.20 (d, 2H, J ) 6.3 Hz),
5.36 (t, 1H, J ) 6.6 Hz), 6.29 (dd, 1H, J ) 5.4, 4.2 Hz), 6.58 (d,
1H, J ) 5.4 Hz), 7.23 (d, 1H, J ) 4.2 Hz); BH cannot be
detected. 13C{1H} NMR (CDCl3): δ 49.89, 52.35, 69.52, 70.61,
104.59, 110.15, 141.36, 153.51; BC cannot be detected. 11B
NMR (CDCl3): δ -13.20 (t, J B-H ) 108.2 Hz). IR (neat, cm-1):
3367 (O-H), 2902 (B-H), 2360 (CtN), 1460 (C-N), 461 (B-
N). MS (ES): m/z (%) 195 (M + 1, 30), 176 (10), 217 (40), 212
(25), 230 (100), 266 (32). Anal. Calcd for C9H15BN2O2: C, 55.71;
H, 7.79; N, 14.44. Found: C, 55.27; H, 7.61; N, 13.98.
125.93, 127.34, 129.44, 129.79; BC cannot be detected. 11B
NMR (CDCl3): δ -13.30 (t, J B-H ) 105.5 Hz). IR (neat, cm-1):
3407 (O-H), 2917 (B-H), 2356 (CtN), 1457 (C-N), 428 (B-
N). MS (ES): m/z (%) 219 (M + 1, 50), 200 (5), 241 (12), 236
(4), 254 (4), 290 (80), 326 (90), 362 (5). Anal. Calcd for C12H19
-
BN2O: C, 66.08; H, 8.78; N, 12.84. Found: C, 65.75; H, 8.61;
N, 12.71.
Dim et h yl(2-o-t olyl-2-h yd r oxyet h yl)a m in e Cya n ob o-
1
r a n e (14). Yellow oil, 85% (0.19 g) yield. H NMR (CDCl3): δ
2.38 (s, 3H), 2.81 (s, 3H), 2.90 (s, 3H), 2.93 (dd, 2H, J ) 5.7,
8.1 Hz), 5.52 (dd, 1H, J ) 3.3, 7.5 Hz), 7.25 (m, 4H); BH cannot
be detected. 13C{1H} NMR (CDCl3): δ 18.87, 49.79, 53.32,
66.60, 68.48, 125.90, 126.24, 126.86, 127.69, 130.49, 130.98;
BC cannot be detected. 11B NMR (CDCl3): δ -13.20 (t, J B-H
) 104.5 Hz). IR (neat, cm-1): 3396 (O-H), 2939 (B-H), 2349
(CtN), 1464 (C-N), 435 (B-N). MS (ES): m/z (%) 219 (M +
1, 22), 241 (4), 236 (4), 254 (12), 290 (64), 326 (100), 362 (4).
Anal. Calcd for C12H19BN2O: C, 66.08; H, 8.78; N, 12.84.
Found: C, 65.67; H, 8.68; N, 12.55.
Ack n ow led gm en t. This research was supported in
part by the Alex Grass Center for Drug Design and
Synthesis of Novel Therapeutics and by the David R.
Bloom Center of Pharmacy. We thank the Israeli
Science Foundation for generous support of this work.
Dim eth yl(2-p-tolyl-2-h yd r oxyeth yl)a m in e Cya n obor -
a n e (13). Yellow oil, 87% (0.19 g). 1H NMR (CDCl3): δ 2.34
(s, 3H), 2.80 (s, 3H), 3.85 (s, 3H), 3.02 (d, 2H, J ) 5.7 Hz),
5.29 (t, 1H, J ) 5.7 Hz), 7.17 (m, 4H); BH cannot be detected.
13C{1H} NMR (CDCl3): δ 21.38, 49.86, 65.36, 69.59, 70.18,
OM049816P