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Abstract

A personal selection of 32 recent papers is presented covering various aspects of current developments in bioorganic chemistry and novel natural products such as chlorahupetone A from Chloranthus henryi var. hupehensis.

Chemistry and bioactivity of lindenane sesquiterpenoids and their oligomers

“…2), which can be explained by the presence of highly conjugated units (D 15(4),5(6),7 (11) , D 15(4),5 (6) , D 11, (13) , D 7(11),8(O) , D 7(11),13(O) , D 6 (7) , D 7 (11) , and D 8 (9) ) in LSs. [28][29][30]52 Taking the most abundant and classical [4 + 2] cycloaddition homo-dimer as an example, it is formed by the intermolecular Diels-Alder reaction between D 15(4),5 (6) and D 8 ′ (9 ′ ) . 28 Subsequent oxidative rearrangement further enhances the structural diversity, such as sarglaromatic D, 68 fortunoid A, 69 and chlorahupetone G. 70 Meanwhile, D 15(4),5 (6) can also react with D 11 ′ (13 ′ ) and D 15 ′ (4 ′ ) or other double bonds of the non-LS unit.…”

“…[5][6][7][8][9][10] Since the rst identication of lindeneol from L. strychnifolia in 1925, 5,11 354 natural LS analogs have been discovered in plants from the Lauraceae, 5,6,12,13 Chloranthaceae, [6][7][8]10,[14][15][16][17] Asteraceae, [18][19][20][21][22][23] and Cyperaceae 24 families, and also the marine animal gorgonian corals. 25,26 Due to the highly conjugated double bonds in LSs, 6,7,27 188 LSs exist as homo-oligomers with different skeletons through diverse addition and rearrangement reactions, [5][6][7][8][9][10] such as Diels-Alder [4 + 2] cycloaddition, 28,29 [2 + 2] cycloaddition, 30 and [6 + 6] cycloaddition. 30 It is worth noting that LS and non-LS units (e.g., monoterpene and geranylbenzofuranone) can form heterooligomers with unprecedented structural diversity, which have remarkable differences compared with that of other sesquiterpenoids.…”

“…25,26 Due to the highly conjugated double bonds in LSs, 6,7,27 188 LSs exist as homo-oligomers with different skeletons through diverse addition and rearrangement reactions, [5][6][7][8][9][10] such as Diels-Alder [4 + 2] cycloaddition, 28,29 [2 + 2] cycloaddition, 30 and [6 + 6] cycloaddition. 30 It is worth noting that LS and non-LS units (e.g., monoterpene and geranylbenzofuranone) can form heterooligomers with unprecedented structural diversity, which have remarkable differences compared with that of other sesquiterpenoids. [31][32][33][34][35][36][37] Plants containing LSs have been used as famous natural medicines to treat blood stasis, inammation, drainage, and detoxication.…”

“…The carbon skeletons and plausible biosynthetic pathways of LS oligomers indicate that [4 + 2] cycloaddition, 28,29 [2 + 2] cycloaddition, 30 [6 + 6] cycloaddition, 30 oxygen-involved [2 + 2 + 2] cycloaddition, 34,36,37 C linear linkage from Micheal addition, 66 and O linear linkage from ether or ester bonds 67 are the main polymerization patterns in these homo- and hetero- oligomers (Fig. 2), which can be explained by the presence of highly conjugated units (Δ 15(4),5(6),7(11) , Δ 15(4),5(6) , Δ 11,(13) , Δ 7(11),8(O) , Δ 7(11),13(O) , Δ 6(7) , Δ 7(11) , and Δ 8(9) ) in LSs.…”