Synthesis of caeliferins, elicitors of plant immune responses: accessing lipophilic natural products via cross metathesis - PubMed (original) (raw)

. 2011 Nov 4;13(21):5900-3.

doi: 10.1021/ol202541b. Epub 2011 Oct 12.

Affiliations

Synthesis of caeliferins, elicitors of plant immune responses: accessing lipophilic natural products via cross metathesis

Inish O'Doherty et al. Org Lett. 2011.

Abstract

A cross metathesis (CM)-based synthesis of the caeliferins, a family of sulfooxy fatty acids that elicit plant immune responses, is reported. Unexpectedly, detailed NMR spectroscopic and mass spectrometric analyses of CM reaction mixtures revealed extensive isomerization and homologation of starting materials and products. It is shown that the degree of isomerization and homologation in CM strongly correlates with substrate chain length and lipophilicity. Side-product suppression requires appropriate catalyst selection and use of 1,4-benzoquinone as a hydride scavenger.

© 2011 American Chemical Society

PubMed Disclaimer

Figures

Figure 1

Figure 1

ESI+-MS analysis of CM reaction mixtures showing [M+Na+] for starting material 9 and product 6. Ion signals corresponding to chain shortened and chain extended homologues are shown in red and blue, respectively. Conditions: (a) G-II (0.05 equiv), BQ (0.1 equiv), 40 °C, 20 h; (b) HG-II (0.05 equiv), BQ (0.1 equiv), 40 °C, 20 h; (c) G-I (0.05 equiv), BQ (0.1 equiv), 40 °C, 20 h.

Figure 2

Figure 2

Section of dqfCOSY spectrum of the mixture of 17 and its isomers and homologues, as derived from the corresponding mixture of isomers and homologues of 9 isolated from CM of 8 with 9 using G-II and BQ (600 MHz, CDCl3, see Figure S1 for full spectrum). Intensity of parts of the spectrum was scaled (1.5x, 2.5x).

Figure 3

Figure 3

Amounts of detected homologation and isomerization products correlate with chain lengths of CM reactants. Percentages refer to amounts of homologated products formed in G-II-catalyzed CM without BQ, as determined by ESI+-MS (see Supporting Information for conditions). Additional side product formation occurs due to product isomerization.

Figure 4

Figure 4

Ethylene emission of Arabidopsis seedlings after treatment with synthetic caeliferin solutions; errors bars, s.d.; two-tailed Student’s t-test; *P<0.05, **P<0.005.

Scheme 1

Scheme 1

Caeliferin Structures and Retrosynthesis

Scheme 2

Scheme 2

Synthesis of Caeliferins 1, 3, and 4

References

    1. Alborn HT, Hansen TV, Jones TH, Bennett DC, Tumlinson JH, Schmelz EA, Teal PE. Proc Natl Acad Sci U S A. 2007;104:12976–12981. -PMC -PubMed
    2. Schmelz EA, Engelberth J, Alborn HT, Tumlinson JH, 3rd, Teal PE. Proc Natl Acad Sci U S A. 2009;106:653–657. -PMC -PubMed
    1. Cahiez G, Chaboche C, Jezequel M. Tetrahedron. 2000;56:2733–2737.
    2. Díez E, Dixon DJ, Ley SV, Polara A, Rodríguez F. Helv Chim Acta. 2003;86:3717–3729.
    1. Xu P, Lin W, Zou X. Synthesis. 2002;8:1017–1026.
    1. Grubbs RH, Burk PL, Carr DD. J Am Chem Soc. 1975;97:3265–3267.
    2. Connon SJ, Blechert S. Angew Chem, Int Ed Engl. 2003;42:1900–1923. -PubMed
    3. Chatterjee AK, Choi TL, Sanders DP, Grubbs RH. J Am Chem Soc. 2003;125:11360–11370. -PubMed
    4. Hoveyda AH, Zhugralin AR. Nature. 2007;450:243–251. -PubMed
    1. Schmidt B. Eur J Org Chem. 2004;9:1865–1880.
    2. Courchay FC, Sworen JC, Ghiviriga I, Abboud KA, Wagener KB. Organometallics. 2006;25:6074–6086.

Publication types

MeSH terms

Substances

LinkOut - more resources