Stereochemistry, Total Synthesis, and Biological Evaluation of the New Plant Hormone Solanacol

Abstract

Poly(9,9‐dioctylfluorene) (PFO) with Mn values above 100 000 g mol−1 in a toluene/water system and Mn values up to 600 000 g mol−1 in a THF/water system has been obtained by improved Suzuki polycondensation using a new kind of amphipathic palladium catalyst with self‐phase‐transfer features, which could overcome the disadvantage caused by the immiscible biphasic mixture and accelerate the transmetalation step (see figure).

Tomato strigolactones

“…5,16 Several of the tomato strigolactones identified here were postulated to be intermediates in this conversion 16 and their identification in tomato seems to support this hypothesis. In addition, the stereochemistry of the revised solanacol structure 22,23 matches the stereochemistry of orobanchol which was recently unambiguously determined. 24 The configuration of these two compounds does, however, not match the proposed stereochemistry of 7-oxoorobanchol 21 and 7-hydroxyorobanchol.…”

“…The abundance of most of these near future are likely. Further research and structure identification will be needed to prove this and confirm the postulated to several revisions to proposed structures of naturally occurring strigolactones already 23,24 and additional revisions in the pathway. A better understanding of this will in the near future prove instrumental for designing strategies to fine-tune the strigolactone composition in a plant.…”

Structure-Activity Relationship Studies of Strigolactone-Related Molecules for Branching Inhibition in Garden Pea: Molecule Design for Shoot Branching

“…5-Hydroxy-SL (strigol) and 4-hydroxy-SL (orobanchol; which was at the limit of significance in one experiment) showed less activity (Table I) than 5-acetate-SL (strigyl acetate) and 4-acetate-SL (orobanchyl acetate; e.g. at 500 nM, strigol was significantly less active than strigyl acetate [Kruskal-Wallis rank sum test, P = 0.00047]; Table I), as recently described for solanacol and solanacyl acetate (Chen et al, 2010). In all cases, acetate-SLs were always more active than their corresponding hydroxySLs, with the same dose-dependent activity for orobanchyl acetate, fabacyl acetate, and solanacyl acetate.…”

“…The first analysis of the distribution of SLs in different species suggests that 5-deoxystrigol is generally shared by both monocots and dicots, while orobanchol and orobanchyl acetate, for which structural revisions were recently proposed (Ueno et al, 2011b;Vurro and Yoneyama, 2012), seem to be found in dicots but not in monocots. Solanacol Chen et al, 2010), identified in tobacco (Nicotiana tabacum), is the only SL having an aromatic A-ring. The highly active synthetic analog of strigol, known as GR24 and commonly used in biological experiments, also has an aromatic A-ring (Fig.…”

Characterization of strigolactones exuded by Asteraceae plants

“…In addition, we recently isolated ent-2 0 -epi-5-deoxystrigol and ent-2 0 -epiorobanchol, the immediate precursor of fabacol and fabacyl acetate, from its root exudates, but we could detect neither fabacol nor fabacyl acetate (Xie et al unpublished data). From a synthetic approach, solanacol was shown to be another ent-SL (Chen et al 2010). These results suggest that plants produce both enantiomers of SLs and only those accumulated or produced at relatively larger amounts have been characterized so far.…”