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DOI: 10.1055/s-0029-1218017
Diastereo- and Enantioselective Synthesis of α,β-Disubstituted γ-Bisalkoxycarbonyl Sulfonates
Publication History
Publication Date:
10 September 2009 (online)
Abstract
The asymmetric synthesis of α,β-disubstituted γ-bisalkoxycarbonyl sulfonates is reported. The synthesis is based on the Michael addition of a lithiated enantiopure sulfonate bearing a cheap chiral sugar auxiliary to Knoevenagel acceptors. The reaction proceeds with high asymmetric inductions (ds = 69-96%) and good yields (62-79%). The absolute configuration was determined by X-ray crystal-structure analysis.
Key words
sulfonate - asymmetric synthesis - Michael addition - sugar auxiliary - Knoevenagel acceptor
-
1a
Kalir A.Kalir HH. In The Chemistry of Sulfonic Acids, Esters and their DerivativesPatai S.Rappoport Z. Wiley; New York: 1991. p.767 -
1b
Yoshikawa M.Yamaguchi S.Kunimi K.Matsuda H.Kuno Y.Yamahara J.Murakami N. Chem. Pharm. Bull. 1994, 42: 1226 -
1c
Ovenden SPB.Capon RJ. J. Nat. Prod. 1999, 62: 1246 -
1d
Minami I.Akimoto H.Kondo M.Nomura H. Chem. Pharm. Bull. 1983, 42: 482 -
1e
Dickson JK.Biller SA.Magnin DR.Petrillo EW.Hillyer JW.Hsieh DC.Lan S.Rinehart JK.Gregg RE.Harrity TW.Jolibois KG.Kalinoski SS.Kunselmann LK.Mookhtiar KA.Ciosek CP. J. Med. Chem. 1996, 39: 661 -
1f
Morimoto S.Nomura H.Ishiguro T.Fugono T.Maeda K. J. Med. Chem. 1972, 15: 1105 -
2a
Xie M.Widlanski TS. Tetrahedron Lett. 1996, 37: 4443 -
2b
Huang J.Widlanski TS. Tetrahedron Lett. 1992, 33: 2657 -
3a
Lawrence RM.Biller SA.Dickson JK.Logan JVH.Mignin DR.Sulsky RB.DiMarco JD.Gougoutas JZ.Beyer BD.Taylor SC.Lan S.Ciosek CP.Harrity TW.Jolibois KG.Kunselman LK.Slusarchyk DA. J. Am. Chem. Soc. 1996, 118: 11668 -
3b
Corey EJ.Cimprich KA. Tetrahedron Lett. 1992, 33: 4099 -
4a
Enders D.Vignola N.Berner OM. Angew. Chem. Int. Ed. 2002, 41: 109 -
4b
Enders D.Berner OM.Vignola N.Bats JW. Chem. Commun. 2001, 2498 -
4c
Enders D.Berner OM.Vignola N.Harnying W. Synthesis 2002, 1945 -
4d
Enders D.Harnying W.Vignola N. Synlett 2002, 1727 -
4e
Enders D.Harnying W.Vignola N. Eur. J. Org. Chem. 2003, 3939 -
4f
Enders D.Harnying W. Synthesis 2004, 2910 -
4g
Enders D.Harnying W. ARKIVOC 2004, (ii): 181 -
4h
Enders D.Harnying W.Raabe G. Synthesis 2004, 590 -
4i
Enders D.Adelbrecht J.-C.Harnying W. Synthesis 2005, 2962 -
4j
Harnying W.Kitisriworaphan W.Pohmakotr M.Enders D. Synlett 2007, 2529 -
4k
Enders D.Iffland D. Synthesis 2007, 1837 -
4l
Enders D.Iffland D.Raabe G. Synthesis 2009, 1683 -
5a
Murray RDH.Mendez J.Brown SA. The Natural Coumarins: Occurrence, Chemistry and Biochemistry Wiley; New York: 1982. -
5b
Zabradink M. The Production and Application of Fluorescent Brightening Agents Wiley; New York: 1992. -
5c
Yu D.Xie ML.Morris-Natschke SL.Lee KH. Med. Res. Rev. 2003, 23: 322 -
5d
Wang CJ.Hsieh YJ.Chu CY.LinY L.Tseng TH. Cancer Lett. 2002, 183: 163
References and Notes
CCDC-739752 (3i) contains the supplementary crystallographic data for this paper. These data can be obtained free of charge from the Cambridge Crystallo-graphic Data Centre via www.ccdc.cam.ac.uk/data-request/cif.
7
General Procedure
for the Synthesis of α,β-Disubstituted γ-Alkoxycarbonyl
Sulfonates 3a-j
To a solution of enantiopure
sulfonate 1 (1.0 mmol) in dry THF (10 mL), n-BuLi (1.6 M solution in hexane, 0.63
mL) was added dropwise at -90 ˚C to - 95 ˚C
under argon. The solution was stirred for 1 h, after which the Michael
acceptor 2 (1.0 mmol in 1 mL dry THF) was
added dropwise. The mixture was stirred for 4-6 h at -90 ˚C
to - 95 ˚C. The progress of the reaction was monitored
by TLC. The mixture was quenched with sat. NH4Cl (3 mL).
After separation of the organic layer, the aqueous phase was extracted
with CH2Cl2 (4 × 5
mL). The combined organic layers were dried over MgSO4,
evaporated, and the crude product was purified by flash column chromatography
(silica gel, Et2O-pentane, 1:2) to afford 3a-j.
Dimethyl 2-(2-{5-(2,2-dimethyl-1,3-dioxolan-4-yl)-2,2-dimethyltetrahydrofuro[2,3-
d
][1,3]dioxol-6-yloxy-sulfonyl}-2-phenyl-1-
p
-tolylethyl)malonate (3b)
Yield 454 mg (70%);
colorless solid; ds = 73%; the major diastereomer
was separated by preparative HPLC; de 98%; mp
66-68 ˚C. ¹H NMR
(400 MHz, CDCl3): δ = 1.32,
1.36, 1.37, 1.70 [4 × s, 12
H, (O)2C(CH3)2], 2.32
(s, 3 H, CH3), 3.33 (dd, J = 7.4,
8.5 Hz, 1 H, CHHOC), 3.44, 3.52 (2 × s,
6 H, OCH3), 3.72 (dd, J = 7.0,
8.5 Hz, 1 H, CHHOC), 3.76 [dd, J = 2.5, 8.8
Hz, 1 H, CH(OC)CH(OC)CH2O],
3.81 [d, J = 7.1
Hz, 1 H, CH(CO2)2], 4.13 [dt, J = 2.5, 7.0
Hz, 1 H, CH(OC)CH2O],
4.20-4.26 [m, 2 H, CH(OC)CH(OC)2, CHCH(CO2)2],
4.47 (dd, J = 4.7,
8.8 Hz, 1 H, CHOSO2), 5.60 (d, J = 9.6
Hz, 1 H, PhCHSO3), 5.64 [d, J = 3.6
Hz, 1 H, CH(OC)2], 7.11 (d, J = 8.0
Hz, 2 H, ArH), 7.38-7.46 (m, 7 H, ArH). ¹³C
NMR (100 MHz, CDCl3): δ = 21.1
(CH3), 25.3, 25.9, 26.4, 26.6 [O2C(CH3)2],
47.5 [CHCH(CO2)2], 52.1,
52.3 (OCH3), 54.7 [CH(CO2)2],
64.1 (CH2), 70.7 (PhCHSO3), 73.7 [CH(OC)CH2O], 76.0 [CH(OC)CH(OC)CH2O],
76.6 [CH(OC)CH(OC)2],
76.9 (CHOSO2), 103.2 [CH(OC)2],
109.7, 113.2 [(O)2
C(CH3)2], 128.2,
128.7, 129.2, 129.9, 130.2 (ArCH), 131.4, 132.7, 137.3 (ArC), 167.5,
167.9 (CO2). IR (KBr): 2954, 2986, 1736, 1602, 1516,
1436, 1370, 1163, 1017, 931, 833, 701 cm-¹.
MS (EI, 70 eV): m/z (%) = 633.6
(10) [M+ - CH3], 261.3
(37), 235.3 (66), 205.3 (40), 169.2 (89), 135.3 (100), 127.3 (66).
Anal. Calcd for C32H40O12S (648.6):
C, 59.25; H, 6.21. Found: C, 59.13; H, 6.12.
General Procedure for the Removal of the Chiral Auxiliary
The
sulfonate 3b (0.5 mmol) was dissolved in
a solution of 2% TFA in MeOH-H2O (10:1
mL). The solution was refluxed for 15 h and then evaporated to dryness.
The resulting oil was dissolved in CH2Cl2,
(i-PrO)3CH (5 mmol) was added
dropwise, and the mixture was refluxed for 3 h. The solvent was
removed in vacuo, and the crude product was purified by flash column
chromatography (SiO2, Et2O-pentane,
1:3) to yield the final product 6.
Dimethyl 2-[2-(Isopropoxysulfonyl)-2-phenyl-1-
p
-tolylethyl]malonate
(6)
Yield 107 mg (48%);
colorless solid; mp 72-74 ˚C; de and ee ≥98% (HPLC); [α]D
²² +52.24
(c 0.67, CHCl3). ¹H
NMR (400 MHz, CDCl3): δ = 0.89,
1.03 [2 × d, J = 6.0
Hz, 6 H, (CH
3)2CH],
2.32 (s, 3 H, CH3), 3.42, 3.54 (2 × s,
6 H, OCH3), 3.95 [d, J = 8.0 Hz, 1 H, CH(CO2)2],
4.19 [dd, J = 8.0,
9.1 Hz, 1 H, CHCH(CO2)2],
4.47 (sept, J = 6.0
Hz, 1 H, CHOSO2), 5.13 (d, J = 9.1
Hz, 1 H, PhCHSO3), 7.10 (d, J = 8.0
Hz, 2 H, ArH), 7.30-7.42 (m, 7 H, ArH). ¹³C
NMR (100 MHz, CDCl3): δ = 21.2
(CH3), 22.3, 23.1 [(CH3)2CH], 47.4 [CHCH(CO2)2],
52.3, 52.6 (OCH3), 55.1 [CH(CO2)2], 70.0
(CHSO3), 77.9 (CHOSO2), 128.6, 128.6, 129.0,
130.0, 130.1 (ArCH), 132.3, 132.7, 137.5 (ArC), 167.8, 168.2 (CO2).
IR (KBr): 2987, 2954, 1738, 1596, 1436, 1370, 1213, 1165, 1017,
871, 840, 698 cm-¹. MS (EI, 70 eV): m/z (%) = 448.2
(5.7) [M+], 235.2 (43), 205.2
(21), 135.1 (100). Anal. Calcd for C23H28O7S
(448.2): C, 61.59; H, 6.29. Found: C, 61.31; H, 6.78. HRMS: m/z calcd for C23H28O7S: 448.1550;
found: 448.1552.