Using bromine as a polarity-reversal catalyst to generate acyl radicals Additive-and metal-free, atom-and step-economic, and operationally simple process Using constant lightirradiation to induce and maintain bromine radicals Access carbonyl compounds and deuterated aldehydes with wide substrate scope

Selective deconstructive functionalization of alkenes, other than the well-established olefin metathesis and ozonolysis, to produce densely functionalized molecular scaffolds is highly attractive but challenging. Here we report an efficient photo-mediated deconstructive germinal dihalogenation of carbon-carbon double bonds. A wide range of geminal diiodoalkanes and bromo(iodo)alkanes (>40 examples) are directly prepared from various trisubstituted alkenes, including both cyclic and acyclic olefins. This C=C cleavage is highly chemoselective and produces geminal dihalide ketones in good yields. Mechanistic investigations suggest a formation of alkyl hypoiodites from benzyl alcohols and N-iodoimides, which undergo light-induced homolytic cleavage to generate active oxygen radical species.

Rh-catalyzed highly chemo- and enantioselective hydrogenation of chromone-2-carboxylic acids was first successfully established, providing a wide range of enantiopure chromanone-2-carboxylic acids with excellent results (up to 97% yield and 99%...

Herbaceous peony (Paeonia lactiflora Pall.) is a well-known ornamental plant with abundant flower colors. However, our understanding of the underlying mechanisms of flower color formation is limited. In this study, a wild sample of herbaceous peony (collected from Heze, China) and eight cultivars with different colors were selected for experimental investigation. The Royal Horticultural Society Color Chart was used to determine flower color, and the anatomic structure; cell sap pH value; moisture content (MC); condensed tannin content (Ct); soluble sugar and soluble protein content of the petals; and content and composition of anthocyanin, flavonoids, and carotenoids in the petals were examined. 1) In the white, pinkish white, pale purple, purplish pink, and reddish purple cultivars, deeper color was associated with greater total amounts of anthocyanin (TA). Hypochromic effects were observed for kaempferol-7-O-glucoside (Km7G), myricetin-3-rhamnoside (My3R), and luteolin-7-O-glucoside (Lu7G). The accumulation of quercetin-3-O-glucoside (Qu3G) and lutein affected yellow color formation in the petals. 2) There are papillate epidermal cells in the petals of the wild P. lactiflora sample, ‘Lanyucangjin’, and ‘Dongjingnvlang’. 3) Cell sap pH and MC of the petals of white, pinkish white, pale purple, and purplish pink cultivars were greater than those of the purplish red and most of the reddish purple cultivars. 4) The Ct was greatest in the purplish red cultivars, whereas no condensed tannins were detected in the white, pinkish white, and pale purple cultivars. 5) There were no significant correlations among soluble sugar content, soluble protein content, and the other physiological indications.

Chitosan oligosaccharide (COS), a degradation product of chitosan, is easily accessible, highly bioactive, non-toxic, and well-soluble in water. The effects of COS on the qualitative attributes of tomato fruits were investigated in the current study. COS was administered to tomato plants (Solanum lycopersicum cv. Ruixinghongniu) by foliar spray and root irrigation in alternate cycles at concentrations of 0.5 g·L−1 and 0.16 g L−1, respectively. The experimental outcomes revealed that COS treatment promoted the coloring and softening of tomato fruits. Lycopene, vitamin C, fructose, and glucose levels increased by 49.0%, 25.4%, 30.2%, and 33.4%, respectively, in COS-treated ripe fruits compared to controls. The volatile metabolome showed that COS application also increased the release of ten volatiles correlated with consumer preference (1-penten-3-one, (E)-2-pentenal, (E)-3-hexen-1-ol, (E)-2-heptenal, 2-isobutylthiazole, phenylacetaldehyde, 2-phenylethanol, 6-methyl-5-hepten-2-one, 6-methyl-5-hepten-2-ol, and β-ionone), contributing to an improved tomato flavor. Moreover, increased transcript levels of genes participating in ethylene biosynthesis, perception, and response along with enhanced ethylene production were observed in COS-treated fruits, suggesting that COS may regulate tomato fruit quality via the ethylene pathway. Taken together, our results indicated that the pre-harvest application of COS could improve tomato fruit quality attributes.