References
<A NAME="RD05903ST-1">1</A>
Kimura Y.
Shimada A.
Kusano M.
Yoshii K.
Morita A.
Nishibe M.
Fujioka S.
Kawano T.
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<A NAME="RD05903ST-2">2</A>
Ravi BN.
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121
<A NAME="RD05903ST-3">3</A>
Schuda PF.
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<A NAME="RD05903ST-4">4</A>
Hochlowski J.
Faulkner DJ.
Matsumoto G.
Clardy J.
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For example:
<A NAME="RD05903ST-5A">5a</A> Clerodanes:
Merrit AT.
Ley SV.
Nat. Prod.
Rep.
1992,
243
<A NAME="RD05903ST-5B">5b</A> Glabrins and related systems:
Jonathan LT.
Gbeassor M.
Che C.-T.
Fong HHS.
Farnsworth NR.
LeBreton GC.
Venton DL.
J.
Nat. Prod.
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<A NAME="RD05903ST-5C">5c</A> Azadirachtin:
Ley SV.
Denholm AA.
Wood A.
Nat. Prod. Rep.
1993,
109
For selected recent examples, see:
<A NAME="RD05903ST-6A">6a</A>
Uchiyama M.
Hirai M.
Nagata M.
Katoh R.
Ogawa R.
Ohta A.
Tetrahedron Lett.
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<A NAME="RD05903ST-6B">6b</A>
Donate PM.
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Valdo G.
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Aleman C.
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<A NAME="RD05903ST-6C">6c</A>
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Casillas EG.
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<A NAME="RD05903ST-6D">6d</A>
Pirrung MC.
Lee RL.
J.
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<A NAME="RD05903ST-6E">6e</A> See also:
Vader J.
Sengers H.
de Groot A.
Tetrahedron
1989,
45:
2131 ; and references therein
For example:
<A NAME="RD05903ST-7A">7a</A>
Evans DA.
Tregay SW.
Burgey CS.
Paras NA.
Vojkovsky T.
J. Am. Chem. Soc.
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<A NAME="RD05903ST-7B">7b</A>
Mikami K.
Terada M.
Nakai T.
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1990,
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3949
<A NAME="RD05903ST-8">8</A> For example: Evans D. A., Burgey
C. S., Kozlowski M. C., Tregay S. W.; J. Am.
Chem. Soc.; 1999, 121:
686
For example:
<A NAME="RD05903ST-9A">9a</A>
Evans DA.
Olhava EJ.
Johnson JS.
Janey JM.
Angew.
Chem. Int. Ed.
1998,
24:
3372
<A NAME="RD05903ST-9B">9b</A>
Audrain H.
Thorhauge J.
Hazell RG.
Jorgensen KA.
J. Org. Chem.
2000,
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<A NAME="RD05903ST-10A">10a</A>
Ghosh AK.
Kawahama R.
Tetrahedron
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1999,
40:
1083
<A NAME="RD05903ST-10B">10b</A>
Ghosh AK.
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<A NAME="RD05903ST-11">11</A>
tert-Butyl
pyruvate was prepared according to the procedure of Arnold:
Arnold Z.
Synthesis
1990,
39
<A NAME="RD05903ST-12">12</A>
Preparation of pyruvate 8: Sodium hydrogen sulfate on silica (0.1
g/mmol of hydroxyl prepared according to the procedure
of Breton
[16]
) was added
to a stirred solution of pyruvic acid (4.3 mL, 62.0 mmol) and 2-(trimethyl-silyl)ethanol
(8.0 mL, 56.0 mmol) in DCM (100 mL). The reaction mixture was heated
at reflux overnight. The mixture was then cooled to room temperature,
filtered and the solvent removed in vacuo. The residue was taken
up in EtOAc (50 mL) and washed with saturated sodium bicarbonate
(100 mL) and saturated brine (50 mL). The organic layer was dried
(Na2SO4), filtered and the solvent removed
in vacuo. Purification by flash chromatography (20% EtOAc-petroleum
ether) followed by distillation under reduced pressure gave TMSE-pyruvate 8, (6.54 g, 62% yield) as a colourless
liquid. Rf 0.56 (20% EtOAc-petroleum
ether); bp 100 °C at 2 mmHg; (liquid film)/cm-1 2995,
2899, 1732, 1298, 1251, 1138, 861, 839; δH (300 MHz,
CDCl3) 4.28 (2 H, m), 2.40 (3 H, s), 1.04 (2 H, m), 0.0 (9
H, s); δC (75 MHz, CDCl3) 192.6,
161.4, 65.4, 27.1, 17.7, -1.2; m/z (CI +)
206.1 (94%, M + NH4)+,
(EI+) 145.0 (M
- MeC=O)+,
101.1 (Me3SiCH2CH2)+,
73 (Me3Si)+; Found 206.1211 (M + NH4)+,
C8H20NO3Si requires 206.1212.
<A NAME="RD05903ST-13">13</A>
All novel compounds were fully characterised.
<A NAME="RD05903ST-14">14</A>
Preparation of 13:
Titanium(IV) chloride (0.22 mL, 2.0 mmol) was added to a stirred
solution of 3,4-dihydro-2H-pyran (0.27
mL, 3.0 mmol) and TMSE-pyruvate 8 (0.30
g, 1.5 mmol) in DCM (10 mL) at -78 °C. The reaction
mixture was stirred for 1 h at -78 °C, then at
room temperature for 1 hour. The reaction mixture was poured into
saturated ammonium chloride solution (30 mL) and EtOAc was added (30
mL). The layers were separated and the aqueous phase washed with
additional EtOAc (3 × 25 mL). The combined organic fractions
were washed with saturated brine (1 × 100 mL) and dried
(Na2SO4). The solution was filtered and the solvent
removed in vacuo. Purification by flash chromato-graphy (40% EtOAc-petroleum
ether) gave lactone 13 (0.19 g, 81% yield)
as a pale yellow oil. Rf 0.3 (40% EtOAc-petroleum
ether); (liquid film)/cm-1 2995,
2928, 2858, 1770, 1703, 1446, 1348, 1234, 1037, 1011; δH (300
MHz, CDCl3) 5.45 (1 H, s), 4.08-3.97 (1 H, m),
3.75-3.61 (1 H, m), 2.84-2.72 (1 H, m), 2.24 (1
H, ddd, J = 11.1 Hz, 6.7 Hz,
4.0 Hz), 1.88-1.70 (2 H, m), 1.76 (3 H, s); δC (75
MHz; CDCl3) 170.6, 155.3, 120.4, 97.3, 63.6, 24.8, 22.5,
6.5; m/z (CI +) 171.9
(100%, M + NH4)+,
154.9 (6, M)+; Found (M + NH4)+ 172.0974,
C8H14NO3 requires 172.0974.
<A NAME="RD05903ST-15">15</A>
Preparation of 14:
Potassium permanganate (0.12 g, 0.77 mmol) was added to a stirred
solution of unsaturated lactone 13 (0.12
g, 0.77 mmol) and benzo-18-crown-6 (0.36 g, 1.16 mmol) in CH2Cl2 (10
mL) and the reaction mixture was stirred at room temperature for
3 days. The mixture was poured into water (10 mL) and the layers
separated. The aqueous layer was washed with CH2Cl2 (3 × 10
mL) and the combined organic layers were dried (Na2SO4),
filtered and the solvent was removed in vacuo. Purification by flash chromatography
(50% EtOAc-petroleum ether) gave diol 14 (86 mg, 60% yield) as a light
brown oil. Rf 0.15 (40% EtOAc-petrol);
(liquid film)/cm-1 3425, 2956,
1776, 1174, 1125, 1026, 936, 915; δH (300 MHz;
CDCl3) 5.62 (1 H, s), 3.82-3.74 (1 H, m), 3.73-3.63
(1 H, app dt), 3.00 (1 H, br. s), 2.81 (1 H, br. s), 2.01-1.79
(2 H, m), 1.61-1.45 (2 H, m), 1.38 (3 H, s); δC (75
MHz; CDCl3) 173.8, 103.6, 79.0, 72.6, 62.6, 27.6, 20.5,
16.8; m/z (CI +) 206.0
(100%, M + NH4)+, 188.9
(5, M)+, 172.0 (8, M - OH)+,
126.0 (3, M - CO3H)+, 110.9
(4, C6H7O2); Found (M + NH4)+ 206.1027,
C8H16NO5 requires 206.1028.
<A NAME="RD05903ST-16">16</A>
Breton GW.
J.
Org. Chem.
1997,
62:
8952
