F. Berrée, N. Gernigon, A. Hercouet, C. H. Lin, B. Carboni
SHORT COMMUNICATION
[5]
a) S. Zhu, T. H. Hudson, D. E. Kyle, A. J. Lin, J. Med. Chem.
2002, 45, 3491–3496; b) B. K. Shull, T. Sakai, J. B. Nichols, M.
Koreeda, J. Org. Chem. 1997, 62, 8294–8303; c) A. B. Charette,
B. Côté, S. Monroc, S. Prescott, J. Org. Chem. 1995, 60, 6888–
6894; d) J. Mulzer, G. Funk, Synthesis 1995, 101–112; e) A.
Sobti, G. A. Sulikowski, Tetrahedron Lett. 1994, 35, 3661–
3664; f) A. B. Charette, B. Côté, Tetrahedron Lett. 1993, 34,
6833–6836; g) S. D. Burke, G. J. Pacofsky, A. D. Piscopio, J.
Org. Chem. 1992, 57, 2228–2235.
[6]
[7]
a) F. Possémé, M. Deligny, F. Carreaux, B. Carboni, J. Org.
Chem. 2007, 72, 984–989; b) M. Lombardo, S. Morganti, M.
Tozzi, C. Trombini, Eur. J. Org. Chem. 2002, 2823–2830; c) L.
Carosi, H. Lachance, D. G. Hall, Tetrahedron Lett. 2005, 46,
8981–8985; d) R. W. Hoffmann, Pure Appl. Chem. 1988, 60,
123–130.
For reviews on allylation chemistry, see: a) S. E. Dennmark,
N. G. Almstead in Modern Carbonyl Chemistry (Ed.: J. Otera),
Wiley-VCH, Weinheim, 2000, chapter 10, pp. 299–402; b) S. R.
Chemler, W. R. Roush in Modern Carbonyl Chemistry (Ed.: J.
Otera), Wiley-VCH, Weinheim, 2000, chapter 11, pp. 403–490;
c) S. E. Denmark, J. Fu, Chem. Rev. 2003, 103, 2763–2793; d)
J. W. Kennedy, D. Hall in Boronic Acids (Ed.: D. G.Hall),
Wiley-VCH, 2005, pp. 241–274.
Scheme 9. Mitsunobu/metathesis/allylboration sequence.
Conclusions
We have demonstrated that the presence of a boronic es-
ter group efficiently governed the regiochemical course of
a Mitsunobu reaction. On the basis of this behaviour, we
developed three-component reactions of (3-hydroxy-1-pro-
pen-1-yl)boronates, benzoic acids, phenol or N-tosylamines
and aldehydes to access enamides and enol benzoates with
high diastereoselectivity.[22] Further works will be devoted
to more detailed mechanistic investigations and to the
asymmetric version of this sequence.
[8]
For selected examples of α-substituted allylboronates, see: a) J.
Pietruszka, N. Schone, W. Frey, L. Grundl, Chem. Eur. J. 2008,
14, 5178–5197; b) L. Carosi, D. G. Hall, Angew. Chem. Int. Ed.
2007, 46, 5913–5915; c) F. Peng, D. G. Hall, J. Am. Chem. Soc.
2007, 129, 3070–3071; d) F. Peng, D. G. Hall, Tetrahedron Lett.
2007, 48, 3305–3309; e) H. Ito, S. Ito, Y. Sasaki, K. Matsuura,
M. Sawamura, J. Am. Chem. Soc. 2007, 129, 14856–14857; f)
D. G. Hall, Synlett 2007, 1644–1655; g) X. Gao, D. Hall, M.
Deligny, A. Favre, F. Carreaux, B. Carboni, Chem. Eur. J. 2006,
12, 3132; h) E. Beckmann, V. Desai, D. Hoppe, Synlett 2004,
2275–2280; i) R. W. Hoffmann, J. J. Wolff, Chem. Ber. 1991,
124, 563–569; j) M. Andersen, B. Hildebrandt, G. Koester,
R. W. Hoffmann, Chem. Ber. 1989, 122, 1777–1782.
a) C. Morrill, R. H. Grubbs, J. Org. Chem. 2003, 68, 6031–
6034; b) E. Jehanno, M. Vaultier, Tetrahedron Lett. 1995, 36,
4439–4442; c) R. W. Hoffmann, S. Dresely, Synthesis 1988,
103–106.
[9]
Experimental Section
Mitsunobu Reaction/Allylboration Sequence. General Procedure: To
a solution of vinyl boronate 3 (1 mmol) in dry THF (7 mL) under
argon, were added successively triphenylphosphane (315 mg,
1.2 mmol), the nucleophile (1.2 mmol) and di-tert-butyl azodicar-
boxylate (276 mg, 1.2 mmol) at 0 °C. The reaction mixture was
stirred at room temperature for 15 h. The aldehyde (1.5 mmol) was
then added, and the reaction mixture was stirred for 15 h. Saturated
Na2CO3 solution (5 mL) was added, and the mixture was stirred
for 15 h. The solvent was evaporated in vacuo. The residue was
dissolved in ethyl acetate and washed twice with H2O. The organic
phase was dried with MgSO4. The residue was purified by silica gel
chromatography (cyclohexane/ethyl acetate = 95:5 to 80:20) to af-
ford the homoallylic alcohols in 40–79% yield.
[10]
The presence of small amounts of the (Z) isomer (ca. 6% by
1H NMR spectroscopy) cannot be excluded since a set of sig-
nals, which could be attributed to this isomer [mainly a doublet
at δ = 4.95 ppm, CHB(OR)2], was observed in the crude prod-
uct. Due to the chemical instability of such allylboronates, it
has not been possible to isolate this minor compound by
chromatography in order to confirm its structure.
See ref.[2a], p. 1343.
a) M. M. Midland, S. B. Preston, J. Am. Chem. Soc. 1982, 104,
2330–2331; b) M. M. Midland, S. B. Preston, J. Org. Chem.
1980, 45, 747–748.
[11]
[12]
[13]
[14]
The use of DTBAD as Mitsunobu reagent, instead of classic
DEAD, generates reaction by-products that can be easily re-
moved by using an acid quench step with TFA: M. Kiankarimi,
R. Lowe, J. R. McCarthy, J. P. Whitten, Tetrahedron Lett. 1999,
40, 4497–4500.
All the reactions were carried out in two steps: First, addition
of DTBAD to a solution of the alcohol 3, triphenylphosphane
and nucleophile, followed after completion of the reaction
(usually 15 h at room temp.) by the addition of the aldehyde.
In the case of 7, we obtained the same results in term of yield,
purity and diastereoisomeric ratio when the aldehyde was pres-
ent at the beginning of the reaction.
a) E. Beckmann, V. Desai, D. Hoppe, Synlett 2005, 217–222;
b) J. Pietruszka, N. Schoene, Eur. J. Org. Chem. 2004, 5011–
5019; c) A. Schlapbach, R. W. Hoffmann, Eur. J. Org. Chem.
2001, 323–328; d) R. W. Hoffmann, S. Dresely, Chem. Ber.
1989, 122, 903–909.
Supporting Information (see footnote on the first page of this arti-
cle): Full experimental procedures and characterization data for
compounds 3–24.
[1] O. Mitsunobu, M. Yamada, Bull. Chem. Soc. Jpn. 1967, 40,
2380–2383.
[2] a) T. Y. S. But, P. T. Toy, Chem. Asian J. 2007, 2, 1340–1355;
b) O. Mitsunobu, Synthesis 1981, 40, 1–28.
[3] a) A. B. Hughes, M. M. Sleebs, J. Org. Chem. 2005, 70, 3079–
3088; b) X. Liao, Y. Wu, J. K. De Brabander, Angew. Chem.
Int. Ed. 2003, 42, 1648–1652; c) J. McNulty, A. Capretta, V.
Laritchev, J. Dyck, A. J. Robertson, Angew. Chem. Int. Ed.
2003, 42, 4051–4054; d) C. Ahn, P. DeShong, J. Org. Chem.
2002, 67, 1754–1759; e) A. B. Smith, I. G. Safonov, R. M.
Corbett, J. Am. Chem. Soc. 2002, 124, 11102–11113.
[4] The SN2 and SN2Ј denominations refer only to the regiochemi-
stry of the reaction.
[15]
[16]
J. Cossy, C. Rasamison, D. G. Pardo, J. Org. Chem. 2001, 66,
7195–7198.
332
www.eurjoc.org
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2009, 329–333