Synlett 2003(8): 1186-1188
DOI: 10.1055/s-2003-39892
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Total Synthesis of the Phytotoxic Agent Herbarumin II Using Butane Diacetals of Glycolic Acid as Building Blocks

Elena Diez, Darren J. Dixon, Steven V. Ley*, Alessandra Polara, Felix Rodriguez
Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
Fax: +44(1223)336442; e-Mail: svl1000@cam.ac.uk;
Weitere Informationen

Publikationsverlauf

Received 9 April 2003
Publikationsdatum:
11. Juni 2003 (online)

Abstract

The total synthesis of the phytotoxic agent herbarumin II has provided an ideal stage to exploit the utility of butane diacetal (BDA) desymmetrised glycolic acid as a primary building block.

6

Data for (R,R): [α]D 25 -211.5 (c 0.4, CHCl3); mp 40-41 °C in agreement with the following reference: Michel, P.; Ley, S. V. Synthesis 2003, in press.

7

Data for (S,S): [α]D 25 +208.3 (c 1.2, CHCl3); mp 41-42 °C in agreement with the following reference: Michel, P.; Ley, S. V. Synthesis 2003, in press.

8

Minor diastereomer was not detected by 1H NMR.

15

Data for herbarumin II: δH (600 MHz, MeOH-d 4) 5.57 (1 H, ddd, J = 15.6 Hz, 2.0 Hz, 1.0 Hz, CH=CH), 5.51 (1 H, dddd, J = 15.6 Hz, 9.9 Hz, 4.1 Hz, 2.0 Hz, CH=CH), 5.17 (1 H, td, J = 9.3 Hz, 2.6 Hz, CHOCO), 4.34 (1 H, quint, J = 1.9 Hz, CHOH), 3.85 (1 H, dd, J = 10.5 Hz, 2.9 Hz, CHOHCH2), 3.52 (1 H, dd, J = 9.6 Hz, 2.3 Hz, CHOH), 2.28 (1 H, m, CH=CHCH aHb), 2.08 (1 H, m, CHa H b), 1.87 (1 H, m, CHaHbCH cHd) 1.80 (1 H, m, CHCH eHf), 1.76 (1 H, m, CHc H d), 1.55 (1 H, m, CHe H f), 1.44 (1 H, m, CH gHhCH3), 1.34 (1 H, m, CHg H h), 0.93 (3 H, t, J = 7.4 Hz, CH3); δC (100 MHz, MeOH-d 4) 177.7 (C=O), 134.5 (CH), 123.9 (CH), 74.5 (CH), 74.3 (CH), 74.0 (CH), 72.3 (CH), 35.6 (CH2), 35.4 (CH2), 30.1 (CH2), 19.1 (CH2), 14.8 (CH3).