Carbonyl propargylation or allenylation by 3-haloprop-1-yne with tin(n) halides and tetrabutylammonium halides

Article abstract of DOI:10.1039/a806206d

3-Bromoprop-1-yne causes carbonyl propargylation with tin(n) chloride and tetrabutylammonium bromide in water to produce 1-substituted but-3-yn-1-ols, while 3-chloroprop-1-yne causes carbonyl allenylation with tin(II) iodide and tetrabutylammonium iodide in 1,3-dimethylimidazolidin-2-one to produce 1-substituted buta-2,3-dien-1-ols.

Full text of DOI:10.1039/a806206d

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Carbonyl propargylation or allenylation by 3-haloprop-1-yne with tin(II
)
halides and tetrabutylammonium halides
Yoshiro Masuyama,*† Akihiro Ito, Mamiko Fukuzawa, Kohji Terada and Yasuhiko Kurusu
Department of Chemistry, Sophia University, 7-1 Kioicho, Chiyoda-ku, Tokyo 102-8554, Japan
3-Bromoprop-1-yne causes carbonyl propargylation with
tin(II) chloride and tetrabutylammonium bromide in water
to produce 1-substituted but-3-yn-1-ols, while 3-chloroprop-
1-yne causes carbonyl allenylation with tin(II) iodide and
tetrabutylammonium iodide in 1,3-dimethylimidazolidin-
2-one to produce 1-substituted buta-2,3-dien-1-ols.
conditions. The results are summarized in Table 1. The reaction
of 3-bromoprop-1-yne (1, XA = Br) with SnCl2 and TBABr at
50 °C in water led to carbonyl propargylation to produce
1-phenylbut-3-yn-1-ol (3, R = Ph) (entry 7, Method A), while
the reaction of 3-chloroprop-1-yne (1, XA = Cl) with SnI2 and
TBAI at 25 °C in 1,3-dimethylimidazolidin-2-one (DMI) led to
carbonyl allenylation to produce 1-phenylbuta-2,3-dien-1-ol (4,
R = Ph) (entry 13, Method B) [eqn. (1)]. TBAXÚ accelerated
Carbonyl propargylation or allenylation by 3-haloprop-1-yne
with tin(II) chloride is one of the most convenient methods for
introduction of propargyl (prop-2-ynyl) or allenyl functions.1–3
The propargylation or allenylation is promoted by NaI or LiI; it
has been presumed that the actual starting material, which reacts
with tin(II) chloride, is 3-iodoprop-1-yne derived from the in
situ reaction 3-bromoprop-1-yne with NaI or LiI.1,3 We have
found that carbonyl allylation by allylic acetates, allylic
bromides, allylic chlorides and vinyl epoxides with rin(II) halide
can be promoted by tetrabutylammonium bromide (TBABr).4–8
A lack of reaction with TBABr might suggest that LiI is
required to form the intermediate 3-iodoprop-1-yne.3 Tetra-
X'
SnCl2
SnI2
1
TBABr
TBAI
R
R
•
(1)
+
OH
OH
H2O
DMI
RCHO
50 °C
25 °C
3
4
2
the carbonyl propargylation or allenylation; > 0.1 equiv. of
TBAXAAA was required (entries 5–8). In the propargylation the
use of SnCl2 and TBABr (or TBACl) is superior to other
combinations of reagents, while SnI2–TBAI is the best
combination of reagents for the allenylation. 3-Chloroprop-
1-yne (1, XA = Cl) did not react under the same conditions as
those of the propargylation with 1 (XA = Br). Water is a more
effective solvent in the propargylation than some organic polar
solvents, such as DMI and THF, in which both organic
substrates and SnCl2 are soluble (entries 1, 2 and 8). The by-
product produced during the propargylation, 4-phenylbut-3-en-
2-one (5, R = Ph), was probably formed by the hydration of
allenylated product 4 (R = Ph).3 The reaction of 1 (XA = Cl)
and 2 (R = Ph) with SnI2–TBAI did not occur in water, and
proceeded with lower selectivity for the allenylation in DMI–
water (entry 14). Thus, water is unsuitable for the allenylation,
in which DMI is a better solvent than DMF or THF (entries
11–13).
butylammonium halide (TBAXAAA) probably reacts with tin(II
)
halide (SnXB2) to form tetrabutylammonium trihalostannate,
which is more nucleophilic than SnXB2. We thus envisioned that
TBAXÚ would promote carbonyl propargylation or allenylation
by 3-haloprop-1-yne with SnXB2.9,10 We here report that using
different halogens in SnXB2 and TBAXÚ affects the selectivity
between carbonyl propargylation and allenylation by 3-halo-
prop-1-yne; carbonyl propargylation occurs with SnCl2 and
TBABr, while carbonyl allenylation occurs with SnI2 and
TBAI.
The reaction of 3-haloprop-1-yne 1 and benzaldehyde (2, R =
Ph) with SnXB2 and TBAXAAA was investigated under various
Table 1 Propargylation and allenylation of 2 (R = Ph) with SnXAA2 and
a
TBAXAAA
TBA
Yield (%)
3 + 4b
Entry XA XAA XAAA (mmol) Solvent
t/h
5c
Table 2 Either propargylation or allenylation with SnXB2 and TBAXÚ
1
2
3
4
Br Cl Br (1)
Br Cl Br (1)
Br Cl Br (1)
Br Cl Br (1)
DMI
THF
THF–H2Od
CH2Cl2–H2Od
H2O
H2O
H2O
H2O
H2O
H2O
THF
DMF
DMI
DMI–H2Od
24
10
8
8
24
8
25 (100:0)
60 (100:0)
70 (100:0)
58 (100:0)
17 (100:0)
61 (100:0)
70 (100:0)
72 (100:0)
44 (100:0)
58 (100:0)
91 (31:69)
91 (19:81)
78 (4:96)
4
9
8
12
0
13
9
10
9
15
0
0
0
Yield (%)
3 + 4b
R
Methoda t/h
5c
5
Br Cl
—
4-MeO2CC6H4
4-MeO2CC6H4
4-NCC6H4
4-NCC6H4
4-MeC6H4
4-MeC6H4
4-MeOC6H4
4-MeOC6H4
Me(CH2)6
Me(CH2)6
c-C6H11
A
B
A
B
A
B
A
B
A
B
A
B
7
24
16
23
20
23
16
25
12
90d
12
88d
75 (100:0)
80 (17:83)
77 (100:0)
62 (2:98)
70 (100:0)
53 (7:93)
62 (100:0)
50 (5:95)
63 (100:0)
50 (7:93)
48 (100:0)
71 (20:80)
14
0
4
0
4
0
4
0
0
0
7
0
6
Br Cl Br (0.1)
Br Cl Br (0.3)
Br Cl Br (1)
Br Cl Br (1)
Br Br Br (1)
7e
8
8
7
9f
70
10
70
28
23
47
10
11f,g Cl
12f,g Cl
13f,g,h Cl
14f,g Cl
I
I
I
I
I (0.1)
I (0.1)
I (0.1)
I (0.1)
57 (33:67)
11
a
The reaction of 3-haloprop-1-yne (1.5 mmol) and benzaldehyde (1.0
mmol) was carried out with SnXAA2 (1.5 mmol) and TBA in solvent (3 ml)
at 50 °C. b Yields of a mixture of 3 (R = Ph) and 4 (R = Ph). The ratio in
parentheses was determined by 1H NMR analysis (JEOL GX-270 or
L–500). Isolated yields of 5 (R = Ph). Organic solvent–H2O = 1:1.
e Method A. f The reaction was carried out at 25 °C. g NaI (1.5 mmol) was
added. h Method B.
c-C6H11
a Method A: Entry 7 in Table 1. Method B: Entry 13 in Table 1. b Yields of
a mixture of 3 and 4. The ratio in parentheses was determined by 1H NMR
c
d
c
d
analysis (JEOL GX-270 or L–500). Isolated yields. The reaction was
carried out at 0 °C.
Chem. Commun., 1998
2025

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3-chloroprop-1-yne (1, XA = Cl) with SnI2 and NaI. Prop-
2-ynyltriiodotin (7, X = I) probably proceeded via g-addition to
the aldehyde (carbonyl allenylation), without isomerizing to
propa-1,2-dienyltriiodotin (8, X = I), in dry polar solvents such
as DMI and DMF to produce buta-2,3-dien-1-ols 4.‡ In contrast,
X'
+
Bu4NX'''
SnX''2
1
Bu4N+ –SnX3
the isomerization of prop-2-ynylbromodichlorotin (7, X3
=
6
BrCl2), derived from reaction of 3-bromoprop-1-yne (1, XA =
Br) with SnCl2 and TBABr at the organic–aqueous interface, to
propa-1,2-dienylbromodichlorotin (8, X3 = BrCl2) probably
occurred more rapidly at 50 °C than carbonyl allenylation by 7
(X3 = BrCl2).§ The carbonyl propargylation by 8 (X3 = BrCl2)
at 50 °C in water thus produced but-3-yn-1-ols 3.¶
X3 = BrCl2
H2O, 50 °C
•
SnX3
SnX3
7
8
RCHO
RCHO
•
Notes and References
† E-mail: y-masuya@hoffman.cc.sophia.ac.jp
R
R
‡ The carbonyl allenylation by 7 (X = I) seems to have proceeded via an
acyclic antiperiplanar transition state, because of the weakly Lewis acidic
tin in 7 (X = I). See ref. 7 and 8.
OH
OH
3
§
It was shown by 1H NMR analysis (JEOL L–500) that prop-
4
2-ynyltriiodotin (7, X = I), derived from 3-chloroprop-1-yne (1, XA = Cl)
via reaction with SnI2 and NaI in [2H7]DMF, isomerized easily to propa-
1,2-dienyltriiodotin (8, X = I) at 50 °C; J. A. Marshall, R. H. Yu and J. F.
Perkins, J. Org. Chem., 1995, 60, 5550.
¶ The carbonyl propargylation by 8 (X3 = BrCl2), which has a strongly
Lewis acidic tin, seems to have proceeded via a usual six-membered cyclic
transition state.
H2O
R
O
5
1 T. Mukaiyama and T. Harada, Chem. Lett., 1981, 621.
2 G. P. Boldrini, E. Tagliavini, C. Trombini and A. Umani-Ronchi,
J. Chem. Soc., Chem. Commun., 1986, 685.
Scheme 1
3 M. Iyoda, Y. Kanao, M. Nishizaki and M. Oda, Bull. Chem. Soc. Jpn.,
1989, 62, 3380.
4 Y. Masuyama, in Advances in Metal-Organic Chemistry, ed L. S.
Liebeskind, JAI, Greenwich, 1994, vol. 3, p. 255.
5 Y. Masuyama, J. Nakata and Y. Kurusu, J. Chem. Soc., Perkin Trans. 1,
1991, 2598.
6 Y. Masuyama, M. Kishida and Y. Kurusu, J. Chem. Soc., Chem.
Commun., 1995, 1405.
7 Y. Masuyama, M. Kishida and Y. Kurusu, Tetrahedron Lett., 1996, 37,
7103.
8 Y. Masuyama, A. Ito and Y. Kurusu, Chem. Commun., 1998, 315.
9 For selective carbonyl propargylation in Barbier-type procedures, see:
H. Tanaka, T. Hamatani, S. Yamashita and S. Torii, Chem. Lett., 1986,
1461 and references cited therein.
10 For carbonyl propargylation and allenylation, see: H. Yamamoto, in
Comprehensive Organic Synthesis, ed B. M. Trost, Pergamon, Oxford,
1991, vol. 2, p. 81.
The propargylation (Method A) and allenylation (Method B)
of various aldehydes by 3-haloprop-1-yne 1 was carried out
under the conditions which gave the best results for benzalde-
hyde, as summarized in Table 2. Aromatic aldehydes bearing an
electron-donating or 2withdrawing group and aliphatic alde-
hydes can be used to afford the corresponding 1-substituted but-
3-yn-1-ols 3 using the SnCl2–TBABr/water system or the
corresponding 1-substituted buta-2,3-dien-1-ols 4 with the
SnI2–TBAI/DMI system in moderate yields.
A plausible mechanism was illustrated with Scheme 1. The
difference between propargylation using the SnCl2–TBABr/
water system and allenylation using the SnI2–TBAI/DMI
system may be due to the Lewis acidity of the tin, reaction
1
temperature and reaction medium. H NMR (JEOL L–500)
observation in [2H7]DMF at 25 °C revealed that prop-
2-ynyltriiodotin (7, X = I) was first formed via the reaction of
Received in Cambridge, UK, 6th August 1998; 8/06206D
2026
Chem. Commun., 1998