Synthesis of 1,1-bis(trimethylstannyl)cyclopropanes by the SRN1 mechanism

Article abstract of DOI:10.1021/om801104e

The reactions of readily available 1,1-dichlorocy- clopropanes, obtained by addition of dichlorocarbene to alkenes, with Me3Sn- anions are reported. The process is described in terms of a photoinduced SRN1 substitution. The 1,1-bis(trimeth- ylstannyl)cycl

Full text of DOI:10.1021/om801104e

2646
Organometallics 2009, 28, 2646–2649
Synthesis of 1,1-Bis(trimethylstannyl)cyclopropanes by the SRN1
Mechanism
Javier F. Guastavino and Roberto A. Rossi*
INFIQC, Departamento de Qu´ımica Orga´nica, Facultad de Ciencias Qu´ımicas, UniVersidad Nacional de
Co´rdoba, Haya de Torre y Medina Allende, 5000 Co´rdoba, Argentina
ReceiVed NoVember 19, 2008
Table 1. Photoinduced Reactions of
Summary: The reactions of readily aVailable 1,1-dichlorocy-
clopropanes, obtained by addition of dichlorocarbene to alkenes,
with Me3Sn- anions are reported. The process is described in
terms of a photoinduced SRN1 substitution. The 1,1-bis(trimeth-
ylstannyl)cyclopropanes were obtained in good to excellent
isolated yield (71-90%); 7,7-dichloro-2-oxa-bicyclo[4.1.0]heptane
gaVe the 1,1-bis(trimethylstannyl) product in only 40% yield.
1,1-Dichloro-2,2-diphenylcyclopropane (4) with Me3Sn- Anion
reaction
substrate 4
entrya time (min) Cl- (%)b recovered
products (yield, %)c
1
2
60
120
60
60
60
90
97
9
52
36
11%
2%
74%
trace
65%
5 (58%), 6 (8%), 7 (trace)
5 (86%), 6 (11%), 7 (trace)
5 (trace), 6 (trace), 7 (20%)
5 (20%), 6 (trace), 7 (75%)
5 (25%)
3d
4e
5f
The preparation of substituted cyclopropyl rings has been a
subject of considerable efforts in the last 40 years. Due to their
easy conversion to useful reactive intermediates, tin-substituted
cyclopropanes are an important family of compounds of
established application in organic synthesis. Even though 1,2-
bis(trialkylstannyl)cyclopropanes are known,1 their 1,1-ana-
logues are less explored with regard to their preparation,
properties, and applications in organic synthesis.2
a All experiments were performed in liquid ammonia using 2.2 equiv
of Me3Sn- anions with irradiation with two HPI-T 400 W lamps (cooled
with air and water). b Chloride ions were determined potentiometrically
considering two chlorines per mole of substrate. c Yields were
determined by 1H NMR with the internal standard method. d Reaction
performed in the dark. e 20 mol % of 1,4-dinitrobenzene was added.
f One equiv of Me3Sn- anion was used.
A few examples of the reactions of 1,1-dihalocyclopropanes,
mainly of 1,1-dihalonorcarane 1, with sulfur, phosphorus, and
ketone enolate anions have been studied previously. Of interest
were their mechanistic aspects as well as their applications in
the preparation of substituted cyclopropanes. These reactions
afforded low to moderate yields of disubstituted products 2
together with monosubstituted reduced compound 3 (eq 1).3a
Such reactions have not been carried out with Me3Sn- anions.
The unimolecular radical nucleophilic substitution, or SRN1,
reaction is an alternate process by which a nucleophilic
substitution is achieved. Since the scope of this process has been
increased considerably over the last decades, nowadays it serves
as an important synthetic strategy.3 The wide variety of
nucleophiles that can be used, the great functional group
tolerance, and the fact that many carbon-carbon and carbon-
heteroatom bonds can be formed make the SRN1 reaction a
powerful synthetic tool.
We have described the photostimulated reactions of Me3SnNa,
prepared in liquid ammonia through the reaction of chlorotri-
methylstannane with Na metal,4 with several substrates, such
as chloroarenes5 and haloadamantanes6 that afford stannanes
in very good to excellent yields, in reactions that occur by the
SRN1 mechanism, an alternative to the usual Grignard or
organolithium route to stannanes.
* Corresponding author. E-mail: rossi@mail.fcq.unc.edu.ar.
(1) For a review of the synthesis and applications of cyclopropylstan-
nanes, see: Rubina, M.; Gevorgyan, V. Tetrahedron 2004, 60, 3129, and
references therein.
(2) As far as we know there is only one report of the synthesis of their
1,1-analogues, such as 7,7-bis(trimethylstannyl)norcarane; see: Seyferth, D.;
Lambert, R. L., Jr. J. Organomet. Chem. 1975, 88, 287.
(3) For reviews, see: (a) Rossi, R. A.; Pierini, A. B.; Pen˜e´n˜ory, A. B.
Chem. ReV. 2003, 103, 71–167. (b) Rossi, R. A.; Pierini, A. B.; Santiago,
A. N. In Organic Reactions; Paquette, L. A., Bittman, R., Eds.; Wiley &
Sons: New York, 1999; pp 1-271. (c) Rossi, R. A. In Synthetic Organic
Photochemistry; Griesberck, A. G., Mattay, J., Eds.; Marcel Dekker: New
York, 2005; Vol. 12, Chapter 15, pp 495-527.
(4) Kraus, C. A.; Sessions, W. J. Am. Chem. Soc. 1925, 47, 2361.
(5) (a) Yammal, C. C.; Podesta´, J. C.; Rossi, R. A. J. Org. Chem. 1992,
57, 5720. (b) Co´rsico, E. F.; Rossi, R. A. Synlett 2000, 227. (c) Santiago,
A. N.; Basso, S. M.; Montan˜ez, J. P.; Rossi, R. A. J. Phys. Org. Chem.
2006, 19, 829. (d) Bardagi, J. I.; Rossi, R. A. J. Org. Chem. 2008, 73,
4491.
The reaction of alkenes with dihalocarbenes by the phase
transfer catalysis route serves excellently for the synthesis of
1,1-dichlorocyclopropanes.7 This led us to study their reactions
with Me3Sn- anions as a route for the preparation of new 1,1-
bis(trimethylstannyl)cyclopropanes by the SRN1 mechanism.
The reaction of 1,1-dichloro-2,2-diphenylcyclopropane (4)
with Me3SnNa under photostimulation in liquid ammonia for
1 h afforded the disubstituted product 1,1-bis(trimethylstan-
nyl)-2,2-diphenylcyclopropane (5) in 58% yield together with
unreacted substrate (11%) and the monosubstituted reduced
compound 6 (8%) and a trace amount of the monoreduced
product 7 (entry 1 in Table 1). When the reaction time
(7) For reviews on the preparation and synthetic applications of
dihalogenocyclopropanes, see: (a) Halton, B.; Harvey. J. Synlett 2006, 1975.
(b) Banwell, M. G.; Beck, D. A. S.; Stanislawski, P. C.; Sydnes, M. O.;
Taylor, R. M. Curr. Org. Chem. 2005, 9, 1589. (c) Fedorynski, M. Chem.
ReV. 2003, 103, 1099, and references therein.
(6) (a) Santiago, A. N.; Stahl, A. E.; Rodriguez, G. L.; Rossi, R. A. J.
Org. Chem. 1997, 62, 4406. (b) Santiago, A. N.; Toledo, C. A.; Rossi,
R. A. J. Org. Chem. 2002, 67, 2494.
10.1021/om801104e CCC: $40.75
2009 American Chemical Society
Publication on Web 03/24/2009

Notes
Organometallics, Vol. 28, No. 8, 2009 2647
doubled to 2 h, a high yield of 5 (86%) was obtained (entry
2 in Table 1) (eq 2). In a preparative scale reaction carried
out under identical conditions product 5 was isolated in 72%
yield. The reaction proceeded in the dark only sluggishly,
yielding the reduced compound 7 as the main product (20%,
entry 3 in Table 1).
A photoinduced reaction performed in the presence 20 mol
% of 1,4-dinitrobenzene, a good inhibitor of the SRN1 reaction,
gave a high yield of 7 and the disubstituted product 5 in only
20% yield (entry 4 in Table 1). The fact that 5 is not produced
under dark conditions confirms that it is formed by the SRN
1
mechanism. Product 7 is formed by halogen-metal exchange
reaction of the substrate with Me3SnNa (eq 3).8 The compound
8 formed is protonated very fast by liquid ammonia (eq 4). This
is supported by the fact that compound 7 is the main product
when the reaction conditions do not favor the SRN1 process
(absence of light or in the presence of an inhibitor, entries 3
and 4 in Table 1).
generated radical anion 9•- (eq 6) is unstable and fragments
into the corresponding tertiary radical 9• and chloride anion (eq
8). The fact that compound 9 is not formed even when 1 equiv
of the nucleophile was employed suggests that the fragmentation
of the radical anion 9•- is faster than the intermolecular electron
transfer to dichloride 4 (eq 7).
In the reactions of 4 with 1 equiv of the nucleophile, 5 was
the only product formed (entry 5 in Table 1), and 65% of
unreacted 4 was recovered. This result shows that the mono-
substitution product with retention of chlorine 9 is not an
intermediate in the formation of disubstitution product 5 because
it is not formed in these experimental conditions.
In the experiments we noted that disubstituted product 5 is
formed in higher yields if the neat substrate 4 is added to the
reaction flask under irradiation while the system is being
irradiated. When 4 is added neat prior to irradiation or as a
solution in dry ether, the main product of the reactions was the
monosubstituted reduced compound 6. These observations
suggested the operation of a very fast halogen-metal exchange
mechanism (eqs 3 and 4) in conditions that do not favor the
ET mechanism.
Radical 9• couples with the nucleophile, yielding the disub-
stituted product radical anion 5•- (eq 9), which by electron
transfer to 4 closes the propagation steps of the chain reaction.
To test the scope of the reaction, 1,1-dichlorocyclopropanes
10-S-17-S, prepared from the corresponding alkenes, were used
as substrates in the photoinduced SRN1 reaction with Me3Sn-
anions as nucleophile (Table 2).
In summary, we have demonstrated that 1,1-dichlorocyclo-
propanes react under irradiation with Me3Sn- anions in liquid
ammonia to give 1,1-bis(trimethylstannyl)cyclopropanes in good
to excellent isolated yield.
Experimental Section
In view of the results discussed above the mechanism
sketched in eqs 5-10 can be proposed.
Photostimulated Reactions of 1,1-Dichlorociclopropanes with
-SnMe3 Anions in Liquid Ammonia. The following procedure is
representative of all these reactions. Ammonia (150 mL), previously
dried over Na metal, was distilled into a 250 mL three-neck round-
bottomed flask equipped with a coldfinger condenser at -78 °C
and a magnetic stirrer under a nitrogen atmosphere. To ammonia
was added Me3SnCl (2.2 equiv, 219 mg) and then Na metal in
small pieces. The addition of Na metal continued until the blue
solution from solvated electrons in excess remained for 10 min.
Photoinduced ET to the substrate forms radical 4• and Cl-
ions by an electron transfer (ET) reaction and fragmentation of
the C-Cl bond, which is the first step of the chain propagation
cycle (eq 5). After stannyl anion addition to radical 4• the
(8) It has been demonstrated before that when the halogen-metal
exchange is faster than the SRN1 mechanism, the anion formed is protonated
very rapidly by liquid ammonia; see ref 5a.

2648 Organometallics, Vol. 28, No. 8, 2009
Notes
Table 2. Reactions of Me3Sn- Anions with
1,1-Dichlorocyclopropanesa
71%) was isolated by radial thin-layer chromatography on silica
gel (stabilized with 5% triethylamine) eluting with petroleum ether
as a colorless oil. 1H NMR (Cl3CD): -0.25 (9H, s, 2JHSn ) 52.16,
2
50.4 Hz, CH3Sn), 0.15 (9H, s, JHSn ) 51, 49.3 Hz, CH3Sn), 1.23
(1H, dd, JHH ) 6.8, 4.3 Hz, CH2), 1.40 (1H, t, JHH ) 4.3 Hz, CH2),
2.36 (1H, dd, J ) 6.8, 4.3 Hz, CH), 7.21 (5H, m, CH). 13C NMR
(Cl3CD): -9.78 (1JCSn ) 324.6, 310.2 Hz, CH3Sn), -8.49 (1JCSn
) 329.3, 315.3 Hz, CH3Sn), 2.8 (C), 12.56 (2JCSn ) 27.1, 21.8 Hz,
CH2), 24.79 (2JCSn ) 20.8 Hz, CH),125.94 (CH), 128.15 (CH), 128.9
(CH), 143.5 (C). 119Sn NMR (Cl3CD): δ 20.3, 38,6. HR-MS (EI):
calcd for C14H23 118Sn120Sn 428.9838, found [M - CH3]+ 428.9854.
Anal. Calcd for C15H26Sn2: C, 40.60; H, 5.91; Sn, 53.50. Found:
C, 40.75; H, 5.95.
1,1-Bis(trimethylstannyl)-2,2-diphenylcyclopropane (5). Com-
pound 5 was obtained according to the general procedure and
recrystallized from ethanol as white crystals and isolated in 72%
1
2
yield (155 mg). H NMR (Cl3CD): -0.22 (18H, s, JHSn ) 50.9
3
Hz, CH3Sn), 1.79 (2H, s, JHSn ) 83.9, 56.8 Hz, CH2), 7.13 (2H,
m, CH), 7.23 (4H, t, JHH ) 7.5 Hz, CH), 7.48 (4H, d, JHH ) 7.5
Hz, CH). 13C NMR (Cl3CD): -7.84 (1JCSn ) 326.7, 312.8 Hz,
CH3Sn), 11.15 (C), 19.99 (2JCSn ) 26.3 Hz, CH2), 40.85 (C), 126.31
(CH), 128.43 (CH), 129.54 (CH), 147.36 (C). 119Sn NMR (Cl3CD):
16. Mp: 128.4-129.9 °C. HR-MS (EI): calcd for C20H27120Sn2
507.0151, found [M - CH3]+ 507.0146. Anal. Calcd for C21H30Sn2:
C, 48.52; H, 5.82; Sn, 45.67. Found: C, 48.35; H, 5.83.
1-Trimethylstannyl-2,2-diphenylcyclopropane (6). Compound
6 was obtained from the photoinduced reaction for 120 min (entry
2 in Table 1) and purified by radial thin-layer chromatography on
silica gel eluting with petroleum ether as a colorless oil. 1H NMR
2
(Cl3CD): -0.21 (9H, s, JHSn ) 54.2, 51.9 Hz, CH3Sn), 1.06 (1H,
dd, JHH ) 10.4, 7.8 Hz, CH), 1.42 (1H, dd, JHH ) 10.4, 3.9 Hz,
CH2), 1.51 (1H, JHH ) 7.8, 3.9, Hz, CH2), 7.21 (10H, m, CH). 13
C
NMR (Cl3CD): -9.96 (1JCSn ) 346.8, 331.6 Hz, CH3Sn), 15.13
(CH), 19.64 (2JCSn ) 20.9 Hz, CH2), 33.85 (C), 125.36 (CH), 126.38
(CH), 127.10 (CH), 128.03 (CH), 128.32 (CH), 130.34 (CH), 145.01
(C), 148.04 (C). 119Sn NMR (Cl3CD): 0.1. HR-MS (EI): calcd for
C17H19120Sn2 343.0503, found [M - CH3]+ 343.0508.
1,1-Bis(trimethylstannyl)-2-methyl-2-phenylcyclopropane (11-P).
The compound 11-P (166 mg, 82%) was obtained according to
the general procedure and isolated by radial thin-layer chromatog-
raphy on silica gel eluting with petroleum ether as a colorless oil.
2
1H NMR (Cl3CD): -0.37 (9H, s, JHSn ) 51.6, 49.5 Hz, CH3Sn),
2
0.17 (9H, s, JHSn ) 51.2, 48.6 Hz, CH3Sn), 1.12 (1H, d, JHH
)
)
3
3
3.8, JHSn ) 82.7, 56.8 Hz, CH2), 1.42 (1H, d, JHH ) 3.8, JHSn
83.4, 56.7 Hz, CH2), 1.44 (3H, s, CH3), 7.15 (1H, m, CH), 7.25
(4H, m, CH). 13C NMR (Cl3CD): -8.31(1JCSn ) 325.9, 311.4 Hz,
CH3Sn), -6.74 (1JCSn ) 321.3, 306.1 Hz, CH3Sn), 10.09 (C), 21.4
(2JCSn ) 29, 25.9 Hz, CH2), 30.98 (C), 31.39 (3JCSn ) 45.2, 16.3
Hz, CH3), 126.0 (CH), 128.41 (CH), 128.98 (CH), 148.59 (C). 119Sn
NMR (Cl3CD): δ 15.7, 17.1. HR-MS (EI): calcd for C15H25120Sn2
444.9995, found [M - CH3]+ 445.0006. Anal. Calcd for C16H28Sn2:
C, 41.98; H, 6.16; Sn, 51.86. Found: C, 42.22; H, 6.14.
a The reactions were performed in 150 mL of liquid ammonia with 1
equiv of substrates and 2.2 equiv of the nucleophile and irradiated with
two HPI-T 400 W lamps (cooled with air and water) during 2 h.
bIsolated product yields. cChloride ions were determined potentio-
metrically considering two chlorines per mol of substrate. dYield was
trans-1,1-Bis(trimethylstannyl)-2-methyl-3-phenylcyclopro-
pane (12-P). Compound 12-P was obtained according to the general
procedure and purified by radial thin-layer chromatography on silica
gel eluting with petroleum ether as a colorless oil in 83% yield
(234 mg). 1H NMR (Cl3CD): -0.26 (9H, s, 2JHSn ) 51.7, 49.7 Hz,
1
determined by H NMR with the internal standard method.
After the last addition, when no more solid was present, Me3Sn-
anions were ready for use. The neat substrate 1,1-dichloro-2-
phenylcyclopropane 10-S (1 equiv, 93.5 mg) was added to the
solution when the reaction flask was already being irradiated. The
irradiation was continued for 2 h. The reaction was quenched with
ammonium nitrate, and the ammonia was allowed to evaporate.
Water was added to the residue and the mixture was extracted with
CH2Cl2 (3 × 20 mL) and diethyl ether (2 × 20 mL) The organic
extract was dried over anhydrous MgSO4 and filtered, and the
solvent was removed to leave the crude product as a light colored
oil. The 1,1-bis(trimethylstannyl)cyclopropane (10-P) (158 mg,
CH3Sn), 0.15 (9H, s, 2JHSn ) 51, 49 Hz, CH3Sn), 1.30 (3H, d, JHH
trans
) 5.9 Hz, CH3), 1.76 (1H, dq, JHH ) 5.9 Hz,
J
HH
) 4.3 Hz,
CH), 2.17 (1H, d, transJ ) 4.3 Hz, 3JHSn ) 76.5, 54.1 Hz, CH), 7.13
(3H, m, CH), 7.22 (2H, m, CH). 13C NMR (Cl3CD): -7.91 (1JCSn
) 326.4, 312.5 Hz, CH3Sn), -7.12 (1JCSn ) 322.1, 308.1 Hz,
CH3Sn), 14.79 (C), 20.87 (2JCSn ) 26.9, 17.2 Hz, CH), 21.1 (3JCSn
) 22.9 Hz, CH3), 33.69 (2JCSn ) 26.3, 20.2 Hz, CH), 125.83 (CH),
128.08 (CH), 128.62 (CH), 143.77 (C). 119Sn NMR (Cl3CD): 17,
20.3. HR-MS (EI): calcd for C15H25120Sn2 444.9995, found [M -

Notes
Organometallics, Vol. 28, No. 8, 2009 2649
CH3]+ 445.0005. Anal. Calcd for C16H28Sn2: C, 41.98; H, 6.16;
Sn, 51.86. Found: C, 41.90; H, 6.17.
-5.92 (1JCSn ) 318.5, 304.2 Hz, CH3Sn), 11.63 (C), 23.85 (2JCSn
) 21 Hz, C), 24.28 (3JCSn ) 29 Hz, CH2), 27.95 (3JCSn ) 47.7,
16.9 Hz, CH3), 31.05 (CH3), 32.56 (C), 55.62 (2JCSn ) 42.62, 14.6
Hz, CH2). 119Sn NMR (Cl3CD): 10.9, 15.4. HR-MS (EI): calcd for
C14H31120Sn2 439.0464, found [M - CH3]+ 439.0471. Anal. Calcd
for C15H34Sn2: C, 39.87; H, 7.58; Sn, 52.54. Found: C, 40.02; H,
7.59.
1,1-Bis(trimethylstannyl)-2-(phenyloxymethyl)cyclopropane
(13-P). Compound 13-P was obtained according to the general
procedure. The crude product was distilled under reduced pressure
using a Ku¨gelrohr apparatus and was isolated in 72% yield (95.1
mg) as a light colored oil. 1H NMR (Cl3CD): 0.07 (9H, s, 2JHSn
)
7,7-Bis(trimethylstannyl)norcarane (16-P).2,9 Compound 16-P
was obtained according to the general procedure and was purified
by column chromatography on silica gel eluting with petroleum as
a colorless oil and isolated in 90% (181 mg). 1H NMR (Cl3CD): 0
2
51.4, 49.5 Hz, CH3Sn), 0.1 (9H, s, JHSn ) 52, 50 Hz, CH3Sn),
0.82 (1H, t, JHH ) 4.0, 3JHSn ) 79.5, 61.2 Hz, CH2), 1.05 (1H, dd,
3
JHH ) 6.8, 4.0 Hz, JHSn ) 71.8, 52.5 Hz, CH2), 1.6 (1H, qd, JHH
) 6.9, 3.7 Hz, CH), 3.72 (1H, dd, JHH ) 9.7, 7.3 Hz, CH2), 4.01
(1H, ddt, JHH ) 9.7, 6.6, 2.2 Hz, CH2), 6.89 (2H, m, CH), 6.95
(1H, m, CH), 7.29 (2H, m, CH). 13C NMR (Cl3CD): -9.81 (1JCSn
) 327.5, 314.1 Hz, CH3Sn), -7.63 (1JCSn ) 327.5, 314.1 Hz,
CH3Sn), -4.56 (C), 12.87 (2JCSn ) 24.3 Hz, CH2), 19.49 (CH),
73.36 (3JCSn ) 47.22, 24.3 Hz, CH2), 114.5 (CH), 120.53 (CH),
129.42 (CH), 158.85 (C). 119Sn NMR (Cl3CD): 24.8, 39.8. HR-
MS (EI): calcd for C15H25120Sn2 460.9944, found [M - CH3]+
460.9949.
1,1-Bis(trimethylstannyl)-2-(2-methoxybenzyl)cyclopropane
(14-P). The compound 14-P was obtained according to the general
procedure. It was separated and isolated by radial thin-layer
chromatography on silica gel eluting with petroleum ether as a
colorless oil in 78% yield (39.4 mg). 1H NMR (Cl3CD): 0.03 (9H,
2
2
(9H, s, JHSn ) 50.2, 48.2 Hz, CH3Sn), 0.17 (9H, s, JHSn ) 50.9,
48.6 Hz, CH3Sn), 1.19 (2H, m, CH), 1.30 (4H, m, CH2), 1.55 (2H,
m, CH2), 1.98 (2H, m, CH2). 13C NMR (Cl3CD): -9.2 (1JCSn
)
316.6, 303.1 Hz, CH3Sn), -5.85 (1JCSn ) 319.3, 304.4 Hz, CH3Sn),
7.61 (C), 17.54 (2JCSn ) 24.2 Hz, CH), 21.13 (CH2), 25.63 (3JCSn
41.9, 32.5 Hz, CH2). 119Sn NMR (Cl3CD): δ -1, 38.
)
7,7-Bis(trimethylstannyl)-2-oxa-bicyclo[4.1.0]heptane (17-P).
Compound 17-P was obtained according to the general procedure.
The crude product was distilled under reduced pressure using a
Ku¨gelrohr apparatus, and the compound (17-P) was isolated in 40%
yield (48.6 mg) as a light colored oil. 1H NMR (Cl3CD): 0 (9H, s,
2JHSn ) 51.7, 49.6 Hz, CH3Sn), 0.15 (9H, s, 2JHSn ) 52.9, 50.7 Hz,
CH3Sn), 1.17 (1H, m, CH), 1.56 (3H, m, CH2), 2.1 (1H, m, CH2),
3.6 (3H, m, CH2, CH). 13C NMR (Cl3CD): -9.49 (1JCSn ) 327.98,
313.16 Hz, CH3Sn), -6.17 (1JCSn ) 333.33, 317.5 Hz, CH3Sn),
8.73 (C), 17.94 (2JCSn ) 24.3 Hz, CH), 21.35 (CH2), 22.59 (3JCSn
) 46.37, 36.02 Hz, CH2), 57.52 (2JCSn ) 29.6 Hz, CH), 63.89 (CH2).
119Sn NMR (Cl3CD): -2.3, 26.4. HR-MS (EI): calcd for
C11H23O120Sn2 410.9787, found [M - CH3]+ 410.9796.
2
2
s, JHSn ) 51.4, 48.9 Hz, CH3Sn), 0.06 (9H, s, JHSn ) 51.4, 49.5
3
Hz, CH3Sn), 0.75 (1H, t, JHH ) 3.8 Hz, JHSn ) 79.2, 60.6 Hz,
CH2), 0.91 (1H, dd, JHH ) 6.9, 3.8 Hz, CH2), 1.38 (1H, m, CH),
gem
2.37 (1H, dd,
J
HH
) 15.1, JHH ) 8.3 Hz, CH2), 2.88 (1H, dd,
) 15.1, JHH ) 5.6 Hz, CH2), 3.83 (3H, s, CH3), 6.86 (1H,
gem
J
HH
d, JHH ) 7.9 Hz, CH), 6.93 (1H, td, JHH ) 7.4, 0.9 Hz, CH) 7.20
(1H, td JHH ) 7.8, 1.6 Hz, CH), 7.31 (1H, dd, JHH ) 7.4, 1.4 Hz,
CH). 13C NMR (Cl3CD): -9.8 (1JCSn ) 322.5, 307.7 Hz, CH3Sn),
Acknowledgment. We thank the Agencia Co´rdoba
Ciencia, CONICET, FONCYT, and SECYT, Universidad
Nacional de Co´rdoba, for their continued support of our work
in this area. J.F.G. thanks CONICET and FONCYT for
fellowships.
-7.67 (1JCSn ) 322.8, 309.6 Hz, CH3Sn), -1.82, 14.08 (2JCSn
)
26.9, 24.4 Hz, CH2), 20.32 (2JCSn ) 23.5, 18.9 Hz, CH), 35.88
(3JCSn ) 45.5, 23.4 Hz, CH2), 55.22 (CH3), 110.03 (CH), 120.35
(CH), 126.95 (CH), 129.21 (CH), 130.67 (C), 157.23 (C). 119Sn
NMR (Cl3CD): 22.6, 36.5. HR-MS (EI): calcd for C16H27120Sn2
475.0100, found [M - CH3]+ 475.0110.
Supporting Information Available: Experimental details, refer-
ences for known compounds, complete characterization data of the
compounds, and 1H NMR and 13C NMR spectra of all compounds.
This material is available free of charge via the Internet at
http://pubs.acs.org.
1,1-Bis(trimethylstannyl)-2-methyl-2-neopentylcyclopro-
pane (15-P). Compound 15-P was obtained according to the general
procedure and purified by radial thin-layer chromatography on silica
gel eluting with petroleum ether as a colorless oil in 78% yield
2
(80.5 mg). 1H NMR (Cl3CD): 0.08 (18H, s, JHSn ) 49,5 Hz,
OM801104E
CH3Sn), 0.83 (2H, m, CH2), 0.97 (9H, s, CH3), 1.18 (1H, d, JHH
)
13.9 Hz, CH2), 1,23 (3H, s, CH3), 1.54 (1H, d, JHH ) 13,9 Hz,
(9) Mitchell, T. N.; El-Behairy, M. J. Organomet. Chem. 1979, 172,
293.
CH2). 13C NMR (Cl3CD): -6.25 (1JCSn ) 316.8, 302.4 Hz, CH3Sn),