Synlett 2008(19): 2969-2972  
DOI: 10.1055/s-0028-1083625
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Synthesis of the C9-C21 Fragment of Geldanamycin via a Diastereoselective Substrate-Controlled Hydrogenation

Tony Horneff, Thorsten Bach*
Lehrstuhl für Organische Chemie I, Technische Universität München, Lichtenbergstr. 4, 85747 Garching, Germany
Fax: +49(89)28913315; e-Mail: thorsten.bach@ch.tum.de;
Further Information

Publication History

Received 12 August 2008
Publication Date:
12 November 2008 (online)

Abstract

An Ir-catalyzed diastereoselective hydrogenation was employed to establish the stereogenic center at carbon atom C14 of a C9-C21 fragment of geldanamycin. The fragment was stereoselectively synthesized from d-mannitol in 18 steps.

1

Current address: The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.

24

Analytical Data of 2
[α]D ²0 -14.5 (c 1.89, Et2O). ¹H NMR (360 MHz, CDCl3): δ = -0.01 (s, 3 H), 0.01 (s, 3 H), 0.76 (d, J = 6.6 Hz, 3 H), 0.82-0.92 (m, 9 H), 1.05 (d, J = 6.8 Hz, 3 H), 1.15 (ddd, J = 14.2, 10.3, 2.0 Hz, 1 H), 1.26 (d, J = 7.3 Hz, 6 H), 1.28 (d, J = 6.6 Hz, 6 H), 1.61 (ddd, J = 14.2, 10.7, 3.5 Hz, 1 H), 1.99-2.12 (m, 1 H), 2.18-2.28 (m, 1 H), 2.50 (dd, J = 12.8, 8.3 Hz, 1 H), 2.55 (dd, J = 12.8, 6.7 Hz, 1 H), 3.19 (ddd, J = 10.7, 2.4, 2.0 Hz, 1 H), 3.23 (s, 3 H), 3.55 (dd, J = 7.9, 2.4 Hz, 1 H), 3.79 (s, 3 H), 4.07 (sept, J = 6.6 Hz, 1 H), 4.48-4.62 (m, 1 H), 4.90-5.04 (m, 2 H), 5.20 (s, 2 H), 5.68 (ddd, J = 17.2, 10.3 Hz, 8.5 Hz, 1 H), 7.13 (s, 1 H), 7.30-7.45 (m, 5 H), 7.60 (s, 1 H). ¹³C NMR (90.6 MHz, CDCl3): δ = -4.8, -4.0, 17.7, 18.5, 19.3, 22.2, 22.3, 22.5, 22.5, 26.1, 29.8, 33.6, 36.3, 41.9, 57.1, 60.5, 66.7, 70.9, 76.1, 76.3, 81.1, 104.2, 114.2, 127.6, 128.0, 128.1, 128.8, 136.4, 138.8, 141.7, 141.7, 144.5, 146.9, 153.3. IR (neat): 3432, 2971, 2928, 1738, 1602, 1514, 1471, 1436, 1382, 1372, 1224, 1196, 1111, 1069, 1030, 834, 776 cm. MS (ES+): m/z (%) = 732 (89), 690 (36), 672 (100). HRMS (ES+): m/z calcd for C38H62NO7Si [M + H]+: 672.4290; found: 672.4276.