Download PDF
Synthesis 2011(13): 2131-2135  
DOI: 10.1055/s-0030-1260604
PAPER
© Georg Thieme Verlag Stuttgart ˙ New York

Synthesis and Absolute Configuration of the 7-Phenylhepta-4,6-diyne-1,2-diol Isolated from Bidens pilosa

Shan Cuia,b, Yang Zoua, Yikang Wu*a, Po Gao*b
a State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, P. R. of China
e-Mail: yikangwu@sioc.ac.cn;
b School of Chemistry and Materials, Heilongjiang University, Harbin 150080, P. R. of China
Further Information

Publication History

Received 29 March 2011
Publication Date:
26 May 2011 (online)

    Permissions and Reprints All articles of this category

Corrected by:

Synthesis and Absolute Configuration of the 7-Phenylhepta-4,6-diyne-1,2-diol Isolated from Bidens pilosaSynthesis 2012; 44(19): 3108-3108
DOI: 10.1055/s-0032-1316784

Abstract

The title diynediol was synthesized in enantiopure (>98.4% ee) forms, with the cross coupling of phenylacetylene with either (R)- or (S)-5-benzyloxypent-1-yn-4-ol catalyzed by nickel(II) chloride-copper(I) iodide as the key step. Comparison of the spectroscopic data (especially the optical rotations) for the synthetic and natural samples revealed that the natural diynediol is of S-configuration. The unexpected formation of a pyranone ring at the alkyne terminal when cleaving a benzyl protecting group with acetic anhydride and trimethylsilyl triflate is also detailed; this approach illustrates a novel and mild entry to related pyranones.

Key words

alkynes - alcohols - natural products - coupling - epoxides

7

The propargylic CH2 group in the end product 1 was reported to give rise to a signal at δ = 2.63 (d, J = 6.6 Hz, 2 H) ppm (measured at 300 MHz) in the original isolation paper (see ref. 1). In this work, it is assigned as δ = 2.65 (dd, J = 17, 6.5 Hz, 1 H), 2.60 (dd, J = 17, 6.5 Hz, 1 H) ppm, because, in the 400 MHz spectrum, a doublet of rather low intensity was clearly seen on each side of the rather intense ones (which might be taken as a broadened doublet with a splitting of ca. 6.5 Hz if the small doublets on both sides are overlooked).