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Synlett 2007(10): 1589-1590  
DOI: 10.1055/s-2007-982533
LETTER
© Georg Thieme Verlag Stuttgart · New York

Highly Efficient Synthesis of (+)-Nimbiol and Other Podocarpanes Derivatives from Sclareol

Isidro S. Marcos*, Alvaro Beneitez, Lourdes Castañeda, Rosalina F. Moro, Pilar Basabe, David Diez, Julio G. Urones
Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad de Salamanca, Plaza de los Caídos 1-5, 37008 Salamanca, Spain
Fax: +34(923)294574; e-Mail: ismarcos@usal.es;
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Publication History

Received 23 March 2007
Publication Date:
06 June 2007 (online)

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Abstract

A new access to tricyclic diterpenes of podocarpane ­skeleton has been opened, in excellent overall yields, and an efficient synthesis of (+)-nimbiol from sclareol has been achieved.

Key words

sclareol - diterpenes - podocarpanes - (+)-nimbiol

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[α]D 22 +31 (c = 0.8, CHCl3); mp 245 °C {Lit. [8] [α]D 22 +32.3; mp 250 °C}. IR (film): 3291, 2929, 2869, 1655, 1578, 1458, 1287, 1162, 907, 733, 665 cm-1. 1H NMR (400 MHz, CDCl3): δ = 7.82 (s, 1 H, H-14), 6.75 (s, 1 H, H-11), 5.82 (br s, 1 H, OH), 2.67 (dd, J = 4.4, 18.0 Hz, 1 H, H-6α), 2.58 (dd, J = 13.6, 18.0 Hz, 1 H, H-6β), 2.23 (s, 3 H, ArCH3), 1.83 (dd, J = 4.4, 13.6 Hz, 1 H, H-5), 1.24-1.78 (m, 6 H), 1.20 (s, 3 H, Me-20), 0.98 (s, 3 H, Me-19), 0.92 (s, 3 H, Me-18). 13C NMR (50 MHz, CDCl3): δ = 38.2 (C-1), 19.1 (C-2), 41.5 (C-3), 33.5 (C-4), 49.8 (C-5), 36.2 (C-6), 199.3 (C-7), 124.4 (C-8), 157.3 (C-9), 38.1 (C-10), 109.8 (C-11), 159.7 (C-12), 122.4 (C-13), 131.0 (C-14), 15.4 (ArCH3), 32.8 (C-18), 21.6 (C-19), 23.5 (C-20). HRMS (ESI): m/z [M+] calcd for C18H24O2: 272.1772; found: 272.1776.