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DOI: 10.1055/s-2006-950264
Homo-Cope-Type Five-Carbon Ring-Expansion Reaction via Silyl Enol Ether
Publikationsverlauf
Publikationsdatum:
09. Oktober 2006 (online)
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Abstract
A five-carbon ring-expansion reaction from a cyclohexane derivative fitted with a 3-hydroxy-2-silyloxyprop-1-en-1-yl unit in lieu of one of the C=C double bonds in the Cope rearrangement was studied to synthesize cycloundecanone derivatives. It was found that (E)-triethylsilyl enol ether is necessary for the reaction. The trans-isomer with respect to the cyclohexane ring afforded (2E,8E)-cycloundeca-2,8-dien-1-one, while its cis-isomer afforded (2E,8E)- and (2E,8Z)-isomers in a 1:3 ratio.
Key words
ring expansion - carbocycles - silicon - enol ethers - Cope rearrangement
- 1
Hill RK. In Comprehensive Organic Synthesis Vol. 5:Trost BM. Pergamon; Oxford: 1991. p.785-826 -
2a
Still WC.Murata S.Revial G.Yoshihara K. J. Am. Chem. Soc. 1983, 105: 625 -
2b
Kuroda C.Nakamura T.Hirota H.Enomoto K.Takahashi T. Bull. Chem. Soc. Jpn. 1985, 58: 146 - 3
Giguere RJ.Duncun SM.Bean JM.Purvis L. Tetrahedron Lett. 1988, 29: 6071 -
4a
Trost BM. Angew. Chem., Int. Ed. Engl. 1986, 25: 1 -
4b
Harmata M. Tetrahedron 1997, 53: 6235 -
4c
Chan DMT. In Cycloaddition Reactions in Organic SynthesisKobayashi S.Jørgensen KA. Wiley; Weinheim: 2002. p.57-84 ; see also ref. 7 -
5a
Kuroda C.Kobayashi K.Koito A.Anzai S. Bull. Chem. Soc. Jpn. 2001, 74: 1947 -
5b
Kuroda C.Ito K. Bull. Chem. Soc. Jpn. 1996, 69: 2297 - For examples
-
6a
Kuroda C.Okada M.Shinozaki S.Suzuki H. Tetrahedron 2006, 62: 726 -
6b
Kuroda C.Honda S.Nagura Y.Koshio H.Shibue T.Takeshita T. Tetrahedron 2004, 60: 319 -
6c
Kuroda C.Kasahara T.Akiyama K.Amemiya T.Kunishima T.Kimura Y. Tetrahedron 2002, 58: 4493 -
6d
Kuroda C.Koshio H.Koito A.Sumiya H.Murase A.Hirono Y. Tetrahedron 2000, 56: 6441 -
7a
Kuroda C. Recent Res. Dev. Pure Appl. Chem. 1998, 2: 184 -
7b
Kuroda C.Suzuki H. Curr. Org. Chem. 2003, 7: 115 - 8
Suzuki H.Kuroda C. Tetrahedron 2003, 59: 3157 - 9
Devon TK.Scott AI. Handbook of Naturally Occurring Compounds Vol. 2: Academic Press; New York: 1972. - For recent examples:
-
10a
Fraga BM. Nat. Prod. Rep. 2000, 17: 483 -
10b
Fraga BM. Nat. Prod. Rep. 2001, 18: 650 -
10c
Fraga BM. Nat. Prod. Rep. 2002, 19: 650 -
10d
Fraga BM. Nat. Prod. Rep. 2003, 20: 392 -
10e
Fraga BM. Nat. Prod. Rep. 2004, 21: 669 -
10f
Fraga BM. Nat. Prod. Rep. 2005, 22: 465 - For recent examples:
-
11a
Hanson JR. Nat. Prod. Rep. 2000, 17: 165 -
11b
Hanson JR. Nat. Prod. Rep. 2001, 18: 88 -
11c
Hanson JR. Nat. Prod. Rep. 2002, 19: 125 -
11d
Hanson JR. Nat. Prod. Rep. 2003, 20: 70 -
11e
Hanson JR. Nat. Prod. Rep. 2004, 21: 785 -
11f
Hanson JR. Nat. Prod. Rep. 2005, 22: 594 - 12
Schmidt U.Langner J.Kirschbaum B.Braun C. Synthesis 1994, 1138 - 13
Nakamura E. Tetrahedron Lett. 1981, 22: 663 - 16 Compound 15: Oil. IR (neat): 1658 cm-1. 1H NMR (CDCl3): δ = 0.87-0.96 (1 H, m), 0.89 (9 H, s, t-Bu), 1.15 (1 H, dddd, J = 2.3, 3.5, 12.5, 14.6 Hz), 1.54 (1 H, dt, J = 12.5, 10.0 Hz), 1.93 (1 H, ddt, J = 1.4, 9.5, 12.5 Hz), 2.07 (1 H, ddt, J = 5.6, 14.6, 2.5 Hz), 2.17-2.37 (3 H, m), 2.44-2.54 (2 H, m), 2.81 (1 H, dt, J = 2.5, 11.3 Hz), 5.08-5.20 (1 H, m, CH=CH), 5.30 (1 H, br dt, J = 15.7, 7.5 Hz, CH=CH), 5.90 (1 H, br d, J = 16.1 Hz, CH=CHCO), 6.45 (1 H, ddd, J = 6.0, 9.4, 16.1 Hz, CH=CHCO). 13C NMR (CDCl3): δ = 27.14 (3 C), 30.07, 31.07, 34.20, 34.42, 35.03 (br), 38.86, 49.56, 129.12 (br), 132.31, 136.33, 156.27, 202.97. HRMS: m/z calcd for C15H24O (M+): 220.1827; found: 220.1812
References and Notes
Five-Carbon Ring Expansion: In a 100-mL round-bottomed flask, a solution of 3c (114.4 mg, 0.386 mmol) in anhyd CH2Cl2 (40 mL) was prepared at -60 °C under Ar. To this was added 2,6-lutidine (0.13 mL) and Tf2O (0.1 mL) successively with stirring; stirring was continued for 1 h at the same temperature. A sat. aq solution of NH4Cl was added and the mixture was extracted with CH2Cl2. The organic layer was dried and the solvent was evaporated to afford an oily residue, which was chromatographed on silica gel (3 g; hexane-EtOAc, 95:5) to give 11 (43.7 mg, 69%).
15Compound 11: Oil. IR (neat): 1657 cm-1. 1H NMR (CDCl3): δ = 1.47-1.80 (4 H, m), 2.01-2.10 (2 H, m), 2.21-2.30 (4 H, m), 2.61-2.67 (2 H, m), 5.03 (1 H, dt, J = 15.5, 7.6 Hz, CH=CH), 5.31 (1 H, dt, J = 15.5, 7.7 Hz, CH=CH), 5.90 (1 H, d, J = 16.2 Hz, CH=CHCO), 6.31 (1 H, dt, J = 16.2, 7.5 Hz, CH=CHCO). 13C NMR (CDCl3): δ = 27.28, 28.53, 30.07, 34.21, 34.45, 38.59, 128.81, 132.01, 137.38, 156.96, 202.88. HRMS: m/z calcd for C11H16O (M+): 164.1201; found: 164.1235.
17Compound 19: Oil. IR (neat): 1672 cm-1. 1H NMR (CDCl3): δ =1.64-1.74 (4 H, m), 2.17-2.31 (6 H, m), 2.53-2.57 (2 H, m), 5.36-5.43 (1 H, m, CH=CH), 5.52 (1 H, ddt, J = 10.5, 8.2, 1.7 Hz, CH=CH), 6.19 (1 H, dt, J = 16.2, 1.5 Hz, CH=CHCO), 6.80 (1 H, dt, J = 16.2, 6.7 Hz, CH=CHCO). 13C NMR (CDCl3): δ = 22.92, 25.10, 25.15, 28.50, 32.10, 39.81, 128.81, 129.73, 131.57, 151.11, 203.56. HRMS: m/z calcd for C11H16O (M+): 164.1201; found: 164.1221.