1666
A. Srikrishna, V. Gowri / Tetrahedron: Asymmetry 18 (2007) 1663–1666
methods (SIR 92). Refinement was by full-matrix least-
squares procedures on F2 using SHELXL-97. The non-
hydrogen atoms were refined anisotropically whereas
hydrogen atoms were refined isotropically. Mol. For.
C19H22N2O6; MW = 374.39; light yellow crystal; crystal
m), 1.77–1.68 (2H, m), 1.09 (3H, s) and 0.90 (3H, s)
[2 · tert-CH3], 0.94 (3H, d, J 7.2 Hz, sec-CH3); 13C NMR
(75 MHz, CDCl3 + CCl4): d 150.2 (C), 146.2 (C), 139.7
(C), 136.7 (C), 130.4 (CH), 128.6 (2C, CH), 127.5 (2C,
CH), 113.3 (CH2, C@CH2), 84.8 (CH), 57.1 (CH3,
OCH3), 52.6 (CH), 50.0 (CH), 48.3 (C), 38.5 (CH), 31.4
(CH2), 30.9 (CH3), 23.1 (CH3), 21.3 (CH3), 11.5 (CH3);
HRMS: m/z calcd for C21H28ONa (M+Na): 319.2038;
found: 319.2039.
ꢀ
system: triclinic; space group P1; cell parameters,
˚
˚
˚
a = 6.930(5) A, b = 11.193(7) A, c = 13.047(9) A;
a
3
˚
74.774(11), b 75.890(11), c 83.013(11), V = 945.3(11) A ,
Z = 2, Dc = 1.315 g cmꢁ3, F(000) = 396, l = 0.099 mmꢁ1
.
Total number of l.s. parameters = 248, R1 = 0.0505 for
2754 F0 > 2r(F0) and 0.0652 for all 3500 data.
wR2 = 0.1202, GOF = 1.051, restrained GOF = 1.051 for
all data. An ORTEP diagram is depicted in Figure 1. Crys-
tallographic data have been deposited with the Cambridge
Acknowledgements
We thank the Department of Science and Technology,
New Delhi, for the financial support and the Council of
Scientific and Industrial Research, New Delhi, for the
award of a research fellowship to V.G. We are grateful to
M/s Organica Aromatics (Bangalore) Pvt. Ltd for the gen-
erous gift of campholenaldehyde.
Crystallographic Data Centre (CCDC 634856). For methyl
23
ether 20: ½aꢀD ¼ ꢁ23:9 (c 16.2, CHCl3); IR (neat): mmax
/
cmꢁ1 1514, 1109; H NMR (300 MHz, CDCl3 + CCl4): d
5.10 (1H, br s, H-2), 3.53 (1H, ddd, J 12.6, 8.1 and
5.4 Hz, H-7), 3.26 (3H, s, OCH3), 3.06 (1H, tt, J 7.8 and
2.4 Hz, H-1), 2.32–2.12 (2H, m), 1.70 (1H, ddd, J 12.6,
8.1 and 5.4 Hz), 1.58 (3H, s, olefinic CH3), 1.57–1.44
(1H, m), 0.99 (3H, s) and 0.95 (3H, s) [2 · tert-CH3], 0.78
1
References
(3H, d,
J
7.2 Hz, sec-CH3); 13C NMR (75 MHz,
CDCl3 + CCl4): d 146.1 (C, C-3), 123.5 (CH, C-2), 84.8
(CH, C-7), 57.1 (CH3, OCH3), 50.6 (CH), 49.1 (CH), 46.9
(C, C-4), 36.9 (CH), 30.9 (CH2, C-6), 29.4 (CH3), 22.2
(CH3), 12.6 (CH3), 11.0 (CH3); HRMS: m/z calcd for
1. Faulkner, D. J. Nat. Prod. Rep. 2002, 19, 1.
2. Guella, G.; Pietra, F. Helv. Chim. Acta 2000, 83, 2946.
3. Iliopoulou, D.; Mihopoulos, N.; Vagias, C.; Papazafiri, P.;
Roussis, V. J. Org. Chem. 2003, 68, 7667.
C13H22ONa (M+Na): 217.1204; found: 217.1203. For
4. Srikrishna, A.; Beeraiah, B. Tetrahedron Lett. 2007, 48, 2291;
Srikrishna, A.; Ravi, G.; Satyanarayana, G. Tetrahedron Lett.
2007, 48, 73; Srikrishna, A.; Kumar, P. R.; Gharpure, S. J.
Indian J. Chem. 2006, 45B, 1909; Srikrishna, A.; Satyanara-
yana, G. Tetrahedron: Asymmetry, 2005, 16, 3992.
5. To the best of our knowledge there is no report in the literature
on the synthesis of any neorogiolane either in racemic or
enantiopure form.
25
ketone 23: ½aꢀD ¼ ꢁ32:4 (c 5.1, CHCl3); IR (neat): mmax
/
cmꢁ1 1643, 1605, 871, 837, 755; 1H NMR (300 MHz,
CDCl3 + CCl4): d 7.76 and 7.23 (4H, 2 · d, J 8.1 Hz,
ArH), 6.20 (1H, d, J 2.1 Hz, H-2), 3.60 (1H, q, J 5.4 Hz,
H-7), 3.34 (3H, s, OCH3), 3.40–3.20 (1H, td, J 8.1 and
2.1 Hz, H-1), 2.44 (3H, s, ArCH3), 2.50–2.20 (2H, m),
2.02 (1H, ddd, J 13.8, 6.0 and 3.9 Hz), 1.79 (1H, ddd, J
13.8, 9.9 and 5.1 Hz), 1.40 (3H, s) and 1.25 (3H, s)
[2 · tert-CH3], 1.05 (3H, d, J 9.0 Hz, sec-CH3); 13C NMR
(75 MHz, CDCl3 + CCl4): d 194.4 (C, C@O), 148.4 (C),
144.5 (CH, C-2), 142.1 (C), 137.6 (C), 129.8 (2C, CH),
128.7 (2C, CH), 84.8 (CH, C-7), 56.7 (CH3, OCH3), 53.1
(CH, C-5), 52.4 (CH, C-8), 48.7 (C, C-4), 41.2 (CH, C-1),
31.6 (CH2, C-6), 30.8 (CH3), 22.1 (CH3), 21.7 (CH3), 11.6
(CH3); HRMS: m/z calcd for C20H27O2 (M+H):
6. Srikrishna, A.; Beeraiah, B.; Satyanarayana, G. Tetrahedron:
Asymmetry 2006, 17, 1544.
7. Ye, T.; McKervey, M. A. Chem. Rev. 1994, 94, 1091; Doyle,
M. P. In Comprehensive Organomettalic Chemistry II; Hege-
dus, L. S., Ed.; Pergamon Press: New York, 1995; Vol. 12,
Chapter 5.2; Doyle, M. P.; McKervey, M. A.; Ye, T. ’Modern
Catalytic Methods for Organic Synthesis with Diazo Com-
pounds: From Cyclopropanes to Ylides; John Wiley and Sons:
New York, 1998.
8. The stereochemistry of diol 12 was assigned tentatively on the
assumption of the preferred stereochemistry of starting keto
ester 9. The stereochemistry of allyl alcohol 13 was assigned on
the basis of the preferred approach of the reagent from the exo
face of enone iii. The formation of allyl alcohol 13 from
ketoester 9 could be rationalised via the intermediate alumin-
ium species ii as depicted below, followed by further reduction
of the resultant enone iii.
299.2011; found: 299.2005. For neorogiolapentaene 24:
24
½aꢀD ¼ ꢁ26:5 (c 2.0, CHCl3); IR (neat): mmax/cmꢁ1 1115,
813; 1H NMR (300 MHz, CDCl3 + CCl4): d 7.24 and
7.04 (4H, 2 · d, J 8.1 Hz, ArH), 5.42 (1H, d, J 2.1 Hz, H-
2), 5.19 and 5.03 (2H, 2 · d, J 2.4 Hz, C@CH2), 3.54
(1H, q, J 6.0 Hz), 3.30 (3H, s, OCH3), 3.23–3.13 (1H, td,
J 8.1 and 2.1 Hz), 2.33 (3H, s, ArCH3), 2.32–2.20 (2H,
H
H
H
H
LAH
OR
O
O
13
AlH2
H
H
COOMe
O
9. R = H
ii
iii
i. R = AlH3