References
1a
Edwards RL.
Fawcett V.
Maitland DJ.
Nettleton R.
Shields L.
Whalley AJS.
J. Chem. Soc., Chem. Commun.
1991,
1009
1b Gimbert Y, Chevenier E, Greene AE, Massardier C, and Piettre A. inventors; EP 014025514.
2
Piettre A.
Chevenier E.
Massardier C.
Gimbert Y.
Greene AE.
Org. Lett.
2002,
4:
3139
3a
Kjaer D.
Kjaer A.
Risbjerg E.
J. Chem. Soc., Perkin Trans. 1
1983,
2815
3b
Kjaer A.
Kjaer D.
Acta. Chem. Scand. B
1982,
36:
417
3c To the best of our knowledge, bikaverin is the only natural product prepared to date through the use of this chemistry.
4 Crystal data for 8: C21H12O3 monoclinic. P21/n; a = 7.729 (1) Å, b = 8.127 (3) Å, c = 23.067 (3) Å; β = 95.95 (1)°; V = 1441.1 (5) Å3; D = 1.44 gcm-3; µ = 0.96 cm-1; λ = 0.71073 Å. 2θ
max = 48°. 2501 measured reflections, 2440 independent reflections; 220 parameters. Reflections/parameters ratio: 6.8; R [I>1.1σ(I)] = 5.8%; wR [all data] = 5.8%. G. O. F. (all data) = 1.54. Full lists of fractional atomic co-ordinates, bond lengths and angles, and thermal parameters have been deposited with the Cambridge Crystallographic Data Centre as supplementary publication no. CCDC-247512.
5a
Chiarello J.
Joullié M.
Tetrahedron
1988,
44:
41
5b
Barrett AGM.
Moris TM.
Barton DHR.
J. Chem. Soc., Perkin Trans. 1
1980,
2272
6a
Hauser FM.
Rhee R.
Synthesis
1977,
245
6b
Hauser FM.
Rhee RP.
J. Org. Chem.
1977,
42:
4155
6c
Hauser FM.
Rhee R.
J. Am. Chem. Soc.
1977,
99:
4533
7 For an excellent review of modern methods for the synthesis of naphthalenes, see: de Koning CB.
Rousseau AL.
van Otterlo WAL.
Tetrahedron
2003,
59:
7
8
Graham SL.
Scholz TH.
J. Org. Chem.
1991,
56:
4260
9 For similar transformations, see: Lewis CN.
Spargo PL.
Staunton J.
Synthesis
1986,
944
10 Weinreb amides are superior to acid chlorides for this type of reaction. See: Carpenter TA.
Evans GE.
Leeper FJ.
Staunton J.
Wilkinson MR.
J. Chem. Soc., Perkin Trans. 1
1984,
1043 ; see also ref. 6c
11
Matsumoto N.
Nakashima T.
Isshiki K.
Kuboki H.
Hirano S.-I.
Kumagai H.
Yoshioka T.
Ishizuka M.
Takeuchi T.
J. Antibiotics
2001,
54:
285
12
Roush WR.
Murphy M.
J. Org. Chem.
1992,
57:
6622
13a
Rubottom GM.
Kim C.
J. Org. Chem.
1983,
48:
1550
13b
Cooke MP.
J. Org. Chem.
1986,
51:
951
14
Shi J.
Zhang X.
Neckers DC.
J. Org. Chem.
1992,
57:
4418
15
Procedure for the Preparation of 4 - Polycondensation of 11 and 15b: To a stirred suspension of pentane-washed NaH (79 mg, 3.29 mmol, from a 60% dispersion in mineral oil) in anhyd THF (2.5 mL) under argon at 0 °C was added dropwise a solution of 15b (130 mg, 0.45 mmol) in THF (5.0 mL). The mixture was stirred at 25 °C for 1 h before the addition of a solution of homophthalate 11 (204 mg, 0.76 mmol) in THF (3.5 mL). The resultant mixture was stirred at 25 °C for 2 h and then heated at 80 °C for 20 h (pressure tube). The solution was cooled and aq HCl (6 N) was added, and the resultant mixture was extracted with CHCl3. After the usual workup, the product was flash chromatographed (SiO2, EtOAc in pentane, 30-50%) to give a mixture of 4 and 16 (12% and 25%, respectively, NMR), which was heated in H2O-toluene 5:1 (12 mL) at 180 °C for 16 h (pressure tube). The cooled solution was worked up in the usual way with CHCl3 to afford a solid product, which was triturated with Et2O and filtered to give 4 (79 mg, 37%) as an orange solid. Mp 268-269 °C (CHCl3). IR (neat): 3411, 1649, 1620, 1602 cm-1. 1H NMR (300 MHz, CDCl3): δ = 3.62 (s, 3 H), 3.89 (s, 3 H), 3.90 (s, 3 H), 3.98 (s, 3 H), 4.04 (s, 3 H), 5.16 (s, 2 H), 6.32 (d, J = 2.2 Hz, 1 H), 6.52 (d, J = 2.2 Hz, 1 H), 6.57 (d, J = 2.2 Hz, 1 H), 6.70 (d, J = 2.2 Hz, 1 H), 6.98 (s, 1 H), 7.65 (s, 1 H). 13C NMR (75.4 MHz, CDCl3): δ = 55.5 (CH3), 55.6 (CH3), 56.3 (CH3), 56.4 (CH3), 59.1 (CH3), 73.6 (CH2), 96.9 (CH), 97.9 (CH), 99.6 (CH), 99.8 (CH), 100.8 (CH), 104.4 (C), 108.2 (C), 109.7 (C), 112.4 (C), 119.7 (CH), 137.5 (C), 140.4 (C), 141.8 (C), 152.0 (C), 157.2 (C), 159.8 (C), 161.0 (C), 161.7 (C), 161.8 (C), 163.9 (C), 183.8 (C). MS (DCI, NH3 + isobutane): m/z (%) = 477 (100) [MH+]. HRMS: m/z calcd for C27H24O8: 476.1471. Found: 476.1479 (M
+). Xanthone 4 was identical in all respects with the material prepared earlier
[2]
through the homo-Fries route.
16a Although acetonaphthone 17a was known,
[16b]
the reported yield was only 3.5%. Therefore, a new route was developed (Scheme
[8]
, R = H; 30% overall yield). Acetonaphthone 17b
[16c]
could be prepared through a route analogous to that used for the preparation of acetonaphthone 15b (Scheme
[5]
, N-methoxy-N-methylacetamide replaces 12); however, a route analogous to that used for 17a proved superior (Scheme
[8]
, R = OMe; 52% overall yield).
16b
Yang NC.
Lin LC.
Shani S.
Yang SS.
J. Org. Chem.
1969,
34:
1845
16c
Dodd JH.
Garigipati RS.
Weinreb SM.
J. Org. Chem.
1982,
47:
4045
17 Crystal data for 18d: C26H22O7 triclinic. P-1; a = 10.404 (3) Å, b = 11.124 (3) Å, c = 15.392 (6) Å; α = 67.91 (2)°, β = 77.29 (2)°, γ = 66.97 (2)°. V = 1513.5 (9) Å3; D = 1.49 gcm-3; µ = 1.97 cm-1, λ = 0.56083 Å; 2θ
max = 35.7°. 3863 measured reflections, 3863 independent reflections. 424 parameters. Reflections/parameters ratio: 5; R [I>2σ(I)] = 9.7%; wR [all data] = 9.9%. G. O. F. = 2.22. The poor resolution is due to problems associated with severely disordered CHCl3 molecules in the asymmetric cell and desolvation (capillary tube). Full lists of fractional atomic co-ordinates, bond lengths and angles, and thermal parameters have been deposited with the Cambridge Crystallographic Data Centre as supplementary publication no. CCDC-247513.
18 This procedure for accessing the o-quinone methides was found to be more convenient than that previously used
[2]
based on Saegusa dehydrosilylation.
19 The corresponding unprotected derivatives 19b-d (R1, R2 = H, OH) could also be secured in moderate yield through treatment of the xanthones 18b-d with boron tribromide prior to reduction-hydrolysis
