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Synlett 2011(9): 1285-1287  
DOI: 10.1055/s-0030-1260546
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Highly Diastereoselective Construction of Substituted Pyrrolidines: Formal Synthesis of (-)-Bulgecinine [¹]

Biswanath Das*, Duddukuri Nandan Kumar
Organic Chemistry Division-1, Indian Institute of Chemical Technology, Hyderabad 500 007, India
Fax: +91(40)27193198; e-Mail: biswanathdas@yahoo.com;
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Publikationsverlauf

Received 13 January 2011
Publikationsdatum:
05. Mai 2011 (online)

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Erratum zu diesem Artikel:

Highly Diastereoselective Construction of Substituted Pyrrolidines: Formal Synthesis of (-)-BulgecinineSynlett 2011; 2011(09): e2-e2
DOI: 10.1055/s-0030-1260571

Abstract

A highly diastereoselective synthesis of substituted pyrrolidines has been achieved starting from nonchiral molecule, allyl bromide, or cis-but-2-ene-1,4-diol. The method involves the asymmetric epoxidation and endo-mode epoxide opening with azide nucleophile as the key steps. The method has been applied for the formal synthesis of (-)-bulgecinine.

Key words

substituted pyrrolidine - (-)-bulgecinine - diastereo­selective synthesis - asymmetric epoxidation - endo-mode epoxide opening

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Part 45 in the series ‘Synthetic Studies on Natural Products and Bioactive Compounds’.

1

Part 45 in the series ‘Synthetic Studies on Natural Products and Bioactive Compounds’.

10

Spectral and Analytical Data of Selected Compounds(3-{3-(Benzyloxy)-2-[(4-methoxybenzyl)oxy]propyl}-oxiran-2-yl)methanol (4) [α]D ²5 -16.8 (c 0.9, CHCl3). IR (KBr): νmax = 3449, 1455, 1375, 1248 cm-¹. ¹H NMR (300 MHz, CDCl3): δ = 7.43-7.16 (7 H, m), 6.81 (2 H, d, J = 8.0 Hz), 4.65-4.43 (4 H, m), 3.79 (3 H, s), 3.74-3.63 (2 H, m), 3.62-3.42 (3 H, m), 2.99 (1 H, m), 2.82 (1 H, m), 1.92-1.73 (2 H, m). ¹³C NMR (75 MHz, CDCl3): δ = 158.3, 139.2, 13 2.3, 129.3, 128.8, 128.0, 121.9, 116.0, 73.2, 71.4, 70.7, 70.5, 70.3, 61.2, 56.3, 49.3, 30.7. ESI-MS: m/z = 358 [M]+. Anal. Calcd (%) for C21H26O5: C, 70.39; H, 7.26. Found: C, 70.41; H, 7.21.
2-Azido-6-(benzyloxy)-5-(4-methoxybenzyloxy)hexane-1,3-diol (3)
IR (KBr): νmax = 3390, 2103 cm-¹. ¹H NMR (200 MHz, CDCl3): δ = 7.38-7.16 (7 H, m), 6.81 (2 H, d, J = 8.0 Hz), 4.65-4.44 (4 H, m), 4.07 (1 H, m), 3.85 (1 H, m), 3.78 (3 H, s), 3.56-3.47 (4 H, m), 2.09 (1 H, m), 1.99-1.78 (1 H, m). ¹³C NMR (100 MHz, CDCl3): δ = 158.0, 137.8, 129.5, 128.5, 127.7, 126.7, 116.0, 73.2, 72.8, 70.1, 66.1, 65.5, 62.6, 55.9, 29.8. ESI-MS: m/z = 401 [M]+. Anal. Calcd (%) for C21H27N3O5: C, 62.84; H, 6.73. Found: C, 62.80; H, 6.75.
(4a R ,6 S ,7a S )-6-(Benzyloxymethyl)-2,2-dimethyl-hexahydro[1,3]dioxino[5,4- b ]pyrrole (16)
[α]D ²5 +31.3 (c 1.7, CHCl3). IR (KBr): νmax = 3385, 1600, 1490, 1279 cm-¹. ¹H NMR (300 MHz, CDCl3): δ = 7.37-7.20 (5 H, m), 4.53 (2 H, s), 4.22 (1 H, m), 4.08 (1 H, m), 3.47 (1 H, m), 3.33 (1 H, m), 2.93-2.74 (3 H, m), 2.30 (1 H, m), 1.97-1.71 (2 H, m), 1.48 (6 H, s). ¹³C NMR (75 MHz, CDCl3): δ = 138.8, 129.3, 128.5, 127.8, 100.9, 81.8, 72.6, 72.2, 70.0, 54.0, 36.7, 27.7. ESI-MS: m/z = 277 [M]+. Anal. Calcd (%) for C16H23NO3: C, 69.31; H, 8.30. Found: C, 69.33; H, 8.27.
(4a R ,6 S ,7a S )-Benzyl 6-Hydroxymethyl)-2,2-dimethyl-tetrahydro[1,3]dioxino[5,4- b ]pyrrole-5(6 H )-carboxylate (2) [α]D ²5 -55.4 (c 1.0, CHCl3). ¹H NMR (300 MHz, CDCl3):
δ = 7.32-7.13 (5 H, m), 5.05 (2 H, s), 4.40 (1 H, m), 4.24-4.00 (2 H, m), 3.96-3.65 (4 H, m), 3.07 (1 H, m), 2.63 (1 H, br s), 2.25 (1 H, m), 1.47 (6 H, s). ¹³C NMR (75 MHz, CDCl3): δ = 155.8, 135.5, 129.0, 128.7, 128.5, 127.8, 100.1, 72.0, 68.5, 67.0, 66.2, 61.1, 58.6, 31.4, 29.5, 19.8. ESI-MS: m/z = 321 [M]+. Anal. Calcd (%) for C17H23NO5: C, 63.55; H, 7.17. Found: C, 63.51; H, 7.12.