SCHEME 1
Palladium-Triethylborane-Triggered
Direct and Regioselective Conversion of
Allylic Alcohols to Allyl Phenyl Sulfones†
Srivari Chandrasekhar,* Vannada Jagadeshwar,
Birudaraju Saritha, and Cheryala Narsihmulu
Organic Chemistry Division-I, Indian Institute of Chemical
Technology, Hyderabad-500 007, India
allylsulfinates, displacement of nitro groups, and so
forth.8 Surprisingly, there is no direct one-step conversion
of allyl alcohol to allyl phenyl sulfone,9 which is highly
desirable keeping in mind some of the disadvantages
involved in the halogenation, mesylation, nitration, and
other activation protocols of allyl alcohols. Tamaru et al.
have achieved one-step activation and addition of allyl
alcohol moieties onto active methylene groups and indoles
under a similar set of conditions.10
Received March 21, 2005
In this note, we report the general and direct conver-
sion of allyl alcohol to allyl phenyl sulfone using Pd(OAc)2
(5 mol %), PPh3 (10 mol %), Et3B (200 mol %), and sodium
phenylsulfinate (150 mol %) in hot DMF (80 °C) (Scheme
1). Attempts to trigger this reaction with few easily
accessible Lewis acids such as BF3‚OEt2, AlCl3, and ZnCl2
did not result in the formation of desired product.
We first explored the reaction of cinnamyl alcohol
(Table 1, entry 1) with sodium phenylsulfinate under the
influence of Et3B, Pd(OAc)2, and PPh3 to observe a
smooth conversion to the corresponding phenyl sulfone
1a in a yield of over 80%. To justify the addition of Et3B,
an experiment was carried out in the absence of Et3B to
isolate only 15% of the sulfone product 1a (Table 2).
A few other experiments were also attempted by
changing either the solvent or concentration of catalyst,
but it was observed that the optimum amounts of Et3B
(200 mol %), Pd(OAc)2 (5 mol %), and PPh3 (10 mol %)
were essential. In the second instance, the citronellol
derivative (Table 1, entry 8) was treated under identical
conditions to obtain the corresponding sulfone 8a in
excellent yield without any traces of the allylic re-
arrangement product. A few other cinnamyl alcohol
analogues (entries 2-6) were also ideal precursors for
the transformation. To expand the horizon of this new
method further, the allyl derivatives of the furanose
A combination of Pd(OAc)2 (5 mol %), PPh3 (10 mol %), and
Et3B (200 mol %) promotes the formation of allyl phenyl
sulfones from the allylic alcohols directly with excellent
yields under mild conditions. The activation of an alcohol
group is not necessary which is achieved in situ. The
conjugated dienols also were equally effective for the said
transformation.
The presence of a phenyl sulfonyl group in a scaffold
provides access to multiple diversity.1 This diversity-
driven functionality naturally attracts wide application.
The phenyl sulfone group has the ability to stabilize an
adjacent carbanion and allows new bond formation
reactions. Its utility is enhanced in an “allylic” environ-
ment. The allyl sulfone can now become an electrophile2
and also become an equivalent to a 1,3- or 1,1-dipole, as
perfectly exemplified by Trost et al.3 The phenyl sulfone
group was also utilized as a precursor for the radical/
radical ion source by using SmI24 and other appropriate
reagents.5 The allyl phenyl sulfones are also an excellent
source for regio- and diastereoselective diene synthesis
via a Julia olefination procedure.6 The phenyl sulfonyl
group is usually introduced by SN2 displacement of an
alcohol via a halide or mesylate.7 Alternatives to this are
oxidations of existing phenyl sulfides, rearrangement of
(7) (a) Murakami, T.; Furusawa, K. Synthesis 2002, 4, 479-482. (b)
Trost, B. M.; Schmuff, N. R. J. Am. Chem. Soc. 1985, 107, 396-405.
(8) (a) Trost, B. M.; Braslau, R. J. J. Org. Chem. 1988, 53, 532-
537. (b) Sato, K.; Aoki, M.; Zheng, X. Q.; Noyori, R. Tetrahedron 2001,
57, 2469-2476. (c) Hiroi, K.; Kitayama, R.; Sato, S. J. Chem. Soc.,
Chem. Commun. 1984, 303-305. (d) Hiroi, K.; Kurihara, Y. J. Chem.
Soc., Chem. Commun. 1989, 1778-1780. (e) Ono, N.; Hamamoto, I.;
Kawai, T.; Kaji, A.; Tamura, R.; Kakihana, M. Bull. Chem. Soc. Jpn.
1986, 59, 405-410.
(9) Kunakova, R. V.; Gaisin, R. L.; Sirazova, M. M.; Dzhemilev, U.
M. Izv. Akad. Nauk SSSR, Ser. Khim. 1983, 1, 157-160; Bull. Acad.
Sci. USSR Div. Chem. Sci. (Engl. Transl.) 1983, 32, 133.
(10) (a) Kimura, M.; Futamata, M.; Mukai, R.; Tamaru, Y. J. Am.
Chem. Soc. 2005, 127, 4592-4593. (b) Mukai, R.; Horino, Y.; Tanaka,
S.; Tamaru, Y.; Kimura, M. J. Am. Chem. Soc. 2004, 126, 11138-
11139. (c) Kimura, M.; Horino, Y.; Mukai, R.; Tanaka, S.; Tamaru, Y.
J. Am. Chem. Soc. 2001, 123, 10401-10402. (d) Kimura, M.; Mukai,
R.; Tanigawa, N.; Tanaka, S.; Tamaru, Y. Tetrahedron 2003, 59, 7767-
7777. (e) Horino, Y.; Naito, M.; Kimura, M.; Tanaka, S.; Tamaru, Y.
Tetrahedron Lett. 2001, 42, 3113-3116. (f) Tamaru, Y.; Horino, Y.;
Araki, M.; Tanaka, S.; Kimura, M. Tetrahedron Lett. 2000, 41, 5705-
5709.
† IICT Communication No. 040606.
(1) For reviews, see: (a) Trost, B. M. Bull. Chem. Soc. Jpn. 1988,
61, 107-124. (b) Solladie, G. In Comprehensive Organic Synthesis;
Trost, B. M.; Fleming, I., Eds.; Pergamon Press: Oxford, 1991; vol. 6,
p 157. (c) Simpkins, N. S. In Sulfones in Organic Synthesis; Pergamon
Press: Oxford, 1993. (d) Najera, C.; Yus, M. Tetrahedron 1999, 55,
10547-10568. (e) Procter, D. J. J. Chem. Soc., Perkin Trans. 1 2000,
835-871.
(2) Trost, B. M.; Ghadiri, M. R. J. Am. Chem. Soc. 1984, 106, 7260-
7261.
(3) Trost, B. M.; Schmuff, N. R.; Miller, M. J. J. Am. Chem. Soc.
1980, 102, 5979-5981.
(4) (a) Chandrasekhar, S.; Yu, J.; Falck, J. R. Tetrahedron Lett. 1994,
35, 5441-5444. (b) Claydent, J.; Julia, M. Chem. Commun. 1994,
2261-2262.
(5) (a) Smith, T. A. K.; Whitham, G. H. J. Chem. Soc., Perkin Trans.
1 1989, 313-317. (b) Padwa, A.; Bullock, W. H.; Dyszlewski, A. D. J.
Org. Chem. 1990, 55, 955-964. (c) Ponten, F.; Magnusson, G. J. Org.
Chem. 1996, 61, 7463-7464.
(6) Julia, M.; Nel, M.; Saussine, L. J. Organomet. Chem. 1979, 181,
C17.
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