References and Notes
<A NAME="RU64711ST-1">1</A>
Park H.-R.
Furihata K.
Hayakawa Y.
Shin-ya K.
Tetrahedron Lett.
2002,
43:
6941
<A NAME="RU64711ST-2">2</A>
Kaufman RJ.
Genes
Dev.
1999,
13:
1211
<A NAME="RU64711ST-3">3</A>
Katschinski DM.
Jacobsen EL.
Wiedmann GJ.
Robins HI.
J.
Cancer. Res. Clin. Oncol.
2001,
127:
425
<A NAME="RU64711ST-4">4</A>
Park H.-R.
Chijiwa S.
Furihata K.
Hayakawa Y.
Shin-ya K.
Org.
Lett.
2007,
9:
1457
<A NAME="RU64711ST-5">5</A>
Tanaka H.
Yoshizawa A.
Chijiwa S.
Ueda J.
Takagi M.
Shin-ya K.
Takahashi T.
Chem.
Asian J.
2009,
4:
1114
<A NAME="RU64711ST-6">6</A>
Zografos AL.
Georgiadis D.
Synthesis
2006,
3157
<A NAME="RU64711ST-7">7</A>
Schobert R.
Schlenk A.
Bioorg. Med. Chem.
2008,
16:
4203
<A NAME="RU64711ST-8">8</A>
Takeda K.
Kato H.
Sasahara H.
Yoshii E.
J. Chem. Soc., Chem. Commun.
1986,
1197
<A NAME="RU64711ST-9">9</A>
Takeda K.
Kawanishi E.
Nakamura H.
Yoshii E.
Tetrahedron Lett.
1991,
32:
4925
<A NAME="RU64711ST-10">10</A>
Roush WR.
Reilly ML.
Koyama K.
Brown BB.
J. Org. Chem.
1997,
62:
8708
<A NAME="RU64711ST-11">11</A>
Boeckmann RK.
Shao P.
Wrobleski ST.
Boehmler
DJ.
Heintzelman GR.
Barbosa AJ.
J.
Am. Chem. Soc.
2006,
128:
10572
<A NAME="RU64711ST-12">12</A>
Roush WR.
Barda DA.
Tetrahedron Lett.
1997,
38:
8781
<A NAME="RU64711ST-13">13</A>
Roush WR.
Barda DA.
Tetrahedron Lett.
1997,
38:
8785
<A NAME="RU64711ST-14">14</A>
Jones BD.
La Clair JJ.
Moore CE.
Rheingold AL.
Burkart MD.
Org. Lett.
2010,
12:
4516
<A NAME="RU64711ST-15">15</A>
The ¹H NMR spectrum
of crude 3 indicated that this material is
present as a single diastereomer. Complete consumption of (R)-pulegone was also confirmed
<A NAME="RU64711ST-16">16</A>
Mukaiyama T.
Matsuo J.
Kitagawa H.
Chem.
Lett.
2000,
11:
1250
<A NAME="RU64711ST-17">17</A>
NOESY correlations were observed between
6-Me, 9-Me and 10-Hb of compound 7
Ireland-Claisen rearrangements
of acetates of tertiary alcohols have been reported, see:
<A NAME="RU64711ST-18A">18a</A>
Giró-Mañas C.
Paddock VL.
Bochet CG.
Spivey AC.
White AJP.
Mann I.
Oppolzer W.
J. Am. Chem. Soc.
2010,
132:
5176
<A NAME="RU64711ST-18B">18b</A>
Haning H.
Giró-Mañas C.
Paddock VL.
Bochet CG.
White AJP.
Bernardinelli G.
Mann I.
Oppolzer W.
Spivey AC.
Org.
Biomol. Chem.
2011,
9:
2809
<A NAME="RU64711ST-19">19</A>
Johnson WS.
Werthemann L.
Bartlett WR.
Brocksom TJ.
Li T.-T.
Faulkner DJ.
Petersen MR.
J. Am. Chem. Soc.
1970,
92:
741
<A NAME="RU64711ST-20">20</A>
Fukazawa T.
Shimoji Y.
Hashimoto T.
Tetrahedron: Asymmetry
1996,
6:
1649
<A NAME="RU64711ST-21">21</A>
Bohno M.
Sugie K.
Imase H.
Yusof YB.
Oishi T.
Chida N.
Tetrahedron
2007,
63:
6977
<A NAME="RU64711ST-22">22</A>
Tanimoto H.
Kato H.
Chida N.
Tetrahedron
Lett.
2007,
48:
6267
<A NAME="RU64711ST-23">23</A>
Analytical data for (5R,6S,9S)-6-[2-(tert-butyldimethyl-silyloxy)ethyl]-4-methoxy-6,8,9-trimethyl-1-oxaspiro-[4.5]deca-3,7-dien-2-one
(14): [α]D
²6 -16
(c 0.46, CHCl3); IR (Nujol):
2956, 1760, 1628, 1089, 962 cm-¹; ¹H
NMR (400 MHz, CDCl3): δ = 0.04 (s,
6 H), 0.88 (s, 9 H), 0.89 (s, 3 H), 1.04
(d, J = 7.3 Hz,
3 H), 1.66 (s, 3 H), 1.72-1.83 (m, 2 H), 1.85
(dd, J = 13.7,
6.4 Hz, 1 H), 2.03 (dd, J = 13.7,
10.0 Hz, 1 H), 2.37 (m, 1 H), 3.67-3.75
(m, 2 H), 3.78 (s, 3 H), 4.99 (s, 1 H),
5.10 (s, 1 H); ¹³C NMR (100
MHz, CDCl3): δ =
-5.3, -5.3,
18.2, 19.5, 20.9, 21.2, 25.9, 32.6, 37.6, 39.8, 42.2, 59.2, 60.0,
88.5, 88.9, 127.4, 136.2, 171.9, 186.0; MS (ESI-TOF): m/z [M + Na]+ calcd
for C21H36NaO4Si: 403.2275; found:
403.2247
<A NAME="RU64711ST-24">24</A>
Roush WR.
Barda DA.
Limberakis C.
Kunz RK.
Tetrahedron
2002,
58:
6433
<A NAME="RU64711ST-25">25</A>
Preparation of (5R,6S,9S)-6-[2-(tert-butyldimethylsilyl-oxy)ethyl]-3-[(RS)-1-hydroxybenzyl]-4-methoxy-6,8,9-trimethyl-1-oxaspiro[4.5]deca-3,7-dien-2-one
(15): To a solution of tetronate 14 (21 mg, 0.066 mmol) in THF (2 mL), was
added a solution of tert-butyllithium
(1.0 M in pentane, 49 µL, 0.085 mmol) at -78 ˚C
under argon and the mixture was stirred for 10 min. To the mixture
was then added benzaldehyde (8.6 µL, 0.085 mmol). After
stirring for 20 min, the reaction mixture was poured into saturated
aqueous NH4Cl and extracted with EtOAc. The organic layer
was washed with water and brine, dried over anhydrous MgSO4 and
concentrated in vacuo. The residue was subjected to flash chromatography
over silica gel (hexanes-acetone, 12:1) to give a 6:4 mixture
of diastereomers of 15 (17 mg, 63%)
as an amorphous solid. [α]D
²6 -11
(c 0.46, CHCl3); IR (Nujol):
3423, 1725, 1635, 1067, 836 cm-¹; ¹H
NMR (400 MHz, CDCl3): δ = 0.04, 0.04,
0.05 (3 × s, total 6 H, TBS), 0.88
(s, 3.6 H, TBS), 0.89 (s, 5.4 H, TBS), 0.95 (s,
1.2 H, 6-Me), 0.97 (s, 1.8 H, 6-Me), 1.05 (d, J = 7.3 Hz,
1.8 H, 9-Me), 1.05 (d, J = 6.9 Hz,
1.2 H, 9-Me), 1.63-1.68 (m, 3 H, 8-Me),
1.74-1.83 (m, 2 H, 6-CH2-), 1.88 (dd, J = 13.7, 6.8 Hz,
0.6 H, 10-Ha), 1.94 (dd, J = 13.8,
6.9 Hz, 0.4 H, 10-Ha), 2.05 (m, 1 H,
10-Hb), 2.38 (m, 1 H, 9-H), 3.69-3.77 (m, 2 H,
6-CH2-CH
2-), 3.88
(s, 1.8 H, 4-OMe), 3.94 (s, 1.2 H, 4-OMe), 4.14
(d, J = 10.0 Hz,
0.6 H), 4.33 (d, J = 10.0 Hz, 0.4 H),
5.10 (m, 1 H, 7-H), 5.96 (s, 0.6 H, OH), 5.98
(s, 0.4, OH), 7.25-7.43 (m, 5 H, ArH); ¹³C
NMR (100 MHz, CDCl3): δ = -5.3
(1.2 C), -5.3 (0.8 C), 18.2 (0.4 C),
18.2 (0.6 C), 19.5 (0.4 C), 19.6 (0.6 C),
20.9 (1 C), 21.6 (0.6 C), 21.6 (0.4 C),
25.9 (3 C), 32.6 (1 C), 37.7 (0.6 C),
37.9 (0.4 C), 49.2 (1 C), 42.3 (0.4 C),
42.4 (0.6 C), 59.9 (0.4 C), 59.9 (0.6 C),
60.3 (0.6 C), 60.4 (0.4 C), 67.2 (0.6 C),
67.7 (0.4 C), 87.7 (0.6 C), 87.9 (0.4 C),
103.1 (0.4 C), 103.2 (0.6 C), 125.8 (1.2 C),
125.9 (0.8 C), 127.2 (0.4 C), 127.3 (0.6 C),
127.5 (0.6 C), 127.6 (0.4 C), 128.6 (2 C),
136.0 (0.6 C), 136.2 (0.4 C), 142.9 (0.4 C),
143.1 (0.6 C), 173.5 (0.4 C), 173.7 (0.6 C),
177.9 (0.4 C), 178.4 (0.6 C); MS (ESI-TOF): m/z [M + Na]+ calcd
for C28H42N2NaO5Si: 509.2694;
found: 509.2661
