Lipids fulfill various functions in life as membrane constituents, for energy storage, or as signaling molecules. If the human lipid metabolism is disturbed, this may lead to serious illnesses such as adipositas and its subsequent complications including cardiovascular diseases or diabetes mellitus. Other consequences of a disordered lipid metabolism include brain dysfunctions, especially if the sphingolipid metabolism is affected, which can often be related to a specific genetic mutation. Sensu stricto, lipids are defined as apolar natural products that can be classified as fatty acids, whose derivatives are waxes, triacylglycerides, phospholipids, sphingolipids and glycolipids. Lipids also constitute important post-translational protein modifications in lipoproteins. The amphiphilic nature of compounds such as phospholipids with a polar headgroup and a long apolar chain results in the spontaneous formation of lipid bilayers in aqueous environments. This was likely a crucial process for the origin of life – and certainly still is for all existing living systems that necessarily contain lipid membranes with their interesting and finely balanced biophysical properties.
See also the Thematic Series:
Natural products in synthesis and biosynthesis II
Transition-metal and organocatalysis in natural product synthesis
Biosynthesis and function of secondary metabolites
Graphical Abstract
Figure 1: Macrolactones produced in scent glands of frogs: (Z)-Tetradec-5-en-13-olide (1) or (Z)-tetradec-9-e...
Figure 2: Total ion chromatogram of the gular gland extract of Hyperolius cinnamomeoventris. X: frog anaesthe...
Scheme 1: Synthesis of (9Z,13R)-tetradec-9-en-13-olide (2).
Scheme 2: Synthesis of (5Z,13R)-tetradec-5-en-13-olide ((R)-1). The enantiomer was obtained in a similar sequ...
Figure 3: Mass spectra of A) the natural compound A, B) (Z)-tetradec-5-en-13-olide (1), and C) (Z)-tetradec-9...
Figure 4: Total ion chromatogram of the enantiomer separation of (Z)-1 on a chiral β-TBDMS- Hydrodex phase. T...
Figure 5: Proposed mass spectrometric fragmentation of macrolides 1 and 2 leading to diagnostic ions of the i...
Graphical Abstract
Figure 1: Examples for previously prepared fluorescent fatty acids and our present work.
Scheme 1: Synthesis of fatty acid 3 with one olefinic unit.
Scheme 2: Synthesis of fatty acid 7 with two olefinic units.
Scheme 3: Synthesis of fatty acid 11c with three olefinic units.
Figure 2: Absorption spectra of fatty acids 3, 7 and 11. Solid lines show the UV absorption while dashed line...
Figure 3: Frontier orbital energies (DFT) and their pictorial representation for the chromophoric cores (cc) ...
Graphical Abstract
Scheme 1: Synthetic procedure for the preparation of 10-undecenoic acid methyl ester-based lipoconjugates of ...
Graphical Abstract
Figure 1: (A) Schematic representation of pheromone-induced conjugation tube formation for mating in Tremella...
Figure 2: Chemical structures of (A) surfactin A and (B) poly-γ-glutamic acid.
Figure 3: (A) Two types of posttranslational isoprenylations of ComX variants. The modified tryptophan residu...
Figure 4: (A) Schematic representation of the signal transduction cascade of quorum sensing stimulated by the...
Figure 5: Amino acid sequences of ComX from seven Bacillus strains. The sequences of the mature pheromones ar...
Figure 6: Chemical structure of kawaguchipeptin A. Dimethylallylated tryptophan residues are colored blue.
Graphical Abstract
Figure 1: The structure of butyrolactol A (1).
Figure 2: Cyanobacterial polyketides bearing a tert-butyl group.
Figure 3: Actinomycete metabolites possessing a contiguous 1,2-diol system.
Figure 4: Feeding experiments of 13C-labeled precursors into 1 detected by 2D-INADEQUATE NMR experiments. (a)...
Figure 5: Organization of the biosynthesis gene cluster for 1. Blue, transcriptional regulator; pink, PKS for...
Figure 6: Biosynthetic pathway of hydroxymalonyl-ACP. Adapted from [24].
Figure 7: Incorporation of L-valine-d8 into 1. (a) 1H NMR spectrum of natural 1 and 2H NMR spectrum of L-vali...
Figure 8: Incorporation of 13C- and 2H-labeled precursors into 1.
Graphical Abstract
Figure 1: Secondary metabolites isolated in this study from P. longicirrum.
Figure 2: Structures of secondary metabolites from P. longicirrum as described by Coll et al. in 1985 [13].
Figure 3: Significant 1H,1H COSY correlations as found in compound 1.
Figure 4: Secosterols [22,24] related to 3β,5α,6β-trihydroxy-9-oxo-9,11-secogorgostan-11-ol (1) from P. longicirrum.
Figure 5: Conformational structure of 1 (key NOESY correlations are indicated with blue arrows; coupling cons...
Figure 6: Structure of cembranoid 5. 1H,1H spin systems (A, B and C) are indicated in bold, arrows show key H...
Figure 7: Compound 5 and the most closely related cembranoids from soft corals.
Figure 8: Proposed configuration and selected NOE correlations of bisepoxide 12 (key NOE correlations are ind...
Figure 9: Structures of bisglaucumlids A–C (23–25).
Figure 10: Proposed configuration of the eastern part (rings B, C and D) of isobisglaucumlides B and C (14 and ...
Figure 11: Effect of Phyllodesmium metabolites in different concentrations on predation by Canthigaster soland...
Figure 12: Phylogenetic tree of octocorals relevant as putative food sources for Phyllodesmium spp. Phylogram ...
Graphical Abstract
Figure 1: Top: Chemical structures of cholesterol and hydroxycholesterols with selected numbering for the car...
Figure 2: 2H NMR chain order parameter of the sn-1 chain of (A) POPC-d31 in the absence and in the presence o...
Figure 3: Rate constants for the permeation of dithionite across LUV membranes composed of POPC in the absenc...
Figure 4: Confocal fluorescence images of GUVs containing DOPC/PSM/cholesterol (A), DOPC/PSM/24R-HC (B), DOPC...
Graphical Abstract
Scheme 1: Isoprenoid biosynthetic pathways and examples for their engineering in heterologous production syst...
Scheme 2: Mutational engineering of different classes of terpene synthases. Left side: The natural product of...
Figure 1: Implementation of a microbial cell factory. 1: Selection of enzymes from different species. P450 an...
Graphical Abstract
Figure 1: Chemical structure of PC-C18pPhC18-PC.
Scheme 1: Synthesis of PC-C18pPhC18-PC; TBAF: tetra-n-butylammonium fluoride, TEA: triethylamine, rt: room te...
Figure 2: DSC curves for PC-C18pPhC18-PC (c = 1 mg mL−1 in H2O, solid lines, heating: red, cooling: blue). FT...
Figure 3: TEM image of an aqueous suspension (c = 0.05 mg mL−1) of PC-C18pPhC18-PC. The samples were prepared...
Figure 4: SANS data of a suspension of PC-C18pPhC18-PC (c = 1 mg mL−1 in D2O, scattered data) with IFT analys...
Figure 5: DSC heating (left-hand column) and cooling (right-hand column) scans of different PC-C18pPhC18-PC:p...
Figure 6: TEM images of aqueous suspensions (c = 60 µM or c = 30 µM for C) of PC-C18pPhC18-PC/phospholipid mi...
Figure 7: FTIR spectroscopic data (symmetric CH2 stretching vibration: red squares, right axis; symmetric CD2...
Figure 8: (A) SAXS diffractograms of an equimolar mixture of PC-C18pPhC18-PC/DPPC (c = 10 mg mL−1, scattered ...
Graphical Abstract
Scheme 1: Molecular structures of the archazolids.
Scheme 2: Retrosynthetic analysis of archazolid A by the Menche group.
Scheme 3: Synthesis of north-eastern fragment 5 through a Paterson anti-aldol addition and multiple Still–Gen...
Scheme 4: Synthesis of 4 through an Abiko–Masamune anti-aldol addition.
Scheme 5: Thiazol construction and synthesis of the southern fragment 6.
Scheme 6: Completion of the total synthesis of archazolid A.
Scheme 7: Synthesis of archazolid B (2) by a ring closing Heck reaction of 38.
Scheme 8: Retrosynthetic analysis of archazolid B by the Trauner group.
Scheme 9: Synthesis of acid 40 from Roche ester 41 involving a highly efficient Trost–Alder ene reaction.
Scheme 10: Synthesis of precursor 39 for the projected relay RCM reaction.
Scheme 11: Final steps of Trauner’s total synthesis of archazolid B.
Scheme 12: Overview of the different retrosynthetic approaches for the synthesis of dihydroarchazolid B (3) re...
Scheme 13: Fragment synthesis of 69 towards the total synthesis of 3.
Scheme 14: Organometallic addition of the side chain to access free alcohol 75.
Graphical Abstract
Figure 1: Structure of the (bis)dithienothiophene mechanosensitive flipper probe. Twisted out of planarity by...
Figure 2: Langmuir–Pockels isotherm of a monolayer of flipper mechanophores during the first compression (bla...
Figure 3: OH-stretching vibration (ν(OH); 3600 cm−1) for IRRA spectra of a flipper mechanophore monolayer dur...
Figure 4: Isotherms of DPPC (dark blue), cholesterol (magenta), DPPC/cholesterol (8:2 mol/mol, green), and DP...
Figure 5: Correlation of the hue of a monolayer flipper probe with its measured surface pressure at the water...
Graphical Abstract
Figure 1: Megasynthases – chemistry and modes of action. a) Products of PKS and FAS megasynthases. b) Reactio...
Figure 2: Compartmentalization of synthesis. a) Surface depiction of fungal FAS (PDB-code: 3hmj) with the upp...
Figure 3: Strategies of megasynthase engineering. a) Mix-and-match approach: A hypothetical chimeric PKS is a...
Figure 4: Preserve-and-adapt approach with FAS. C. ammoniagenes FAS has been engineered in two cooperatively ...
Graphical Abstract
Figure 1: Elansolids A1/A2, B1, B2 and A3 (1–4).
Scheme 1: IMDA to generate the tetrahydroindane unit of the elansolids by oxidation of benzyl ether 8 as prec...
Scheme 2: Stille cross-coupling reaction and formation of eastern fragment 13.
Scheme 3: Total synthesis of elansolids B1 (2) and B2 (3).
Graphical Abstract
Figure 1: Chemical structures of the basic compounds used in this study.
Scheme 1: Synthesis of the BODIPY building block (part A) and construct 6 (part B).
Figure 2: Absorbance and fluorescence spectra of compounds 3–6. UV spectra (part A) were recorded with a conc...
Figure 3: NO production in primary rat macrophages. The cells were treated with Tb, compounds 4, 5, and Tb-co...
Figure 4: Atomic force microscopy images of liposomes, 5 µm area: A) 2D image, B) 3D image (Ra = 2.4 nm); 2 µ...
Figure 5: Panel of images from live-cell fluorescence microscopy: intracellular localization of construct 6 i...
Figure 6: Panel of images from live-cell fluorescence microscopy: intracellular localization of liposomes wit...
Graphical Abstract
Figure 1: The major diterpene polyols from croton oil [phorbol (1a), 4α-phorbol (2), 4-deoxy-4α-phorbol (3a)]...
Graphical Abstract
Figure 1: Structure of fusaricidins E (1) and F (2).
Figure 2: NOESY /COSY and HMBC correlations of compound 1.
Figure 3: Fragmentation pattern of compounds 1 and 2.
Scheme 1: Retrosynthetic plan for the depsipeptide and GHPD side chain.
Scheme 2: a) LiAlH4, THF, reflux, 12 h, quant.; b) Fmoc-OSu, NaHCO3, 1,4-dioxane, H2O, 0 °C to rt, 87%; c) 1:...
Scheme 3: Ester bond formation with 2,2-dimethylated pseudoproline including peptide 16.
Scheme 4: Cyclization with 2,2-dimethylated pseudoproline including peptide 16.
Scheme 5: Depsipeptide cyclization and coupling with GHPD side chain.
Figure 4: Byproducts from removal of Cbz group in THF and DMF.
Graphical Abstract
Figure 1: Initial proposal for the core macrolactone structure (left) and the established complete structure ...
Figure 2: Mycolactone congeners and their origins.
Figure 3: Misassigned mycolactone E structure according to Small et al. [50] (11) and the correct structure (6) f...
Figure 4: Schematic illustration of Kishi’s improved mycolactone TLC detection method exploiting derivatizati...
Figure 5: Fluorescent probes derived from natural mycolactone A/B (1a,b) or its synthetic 8-desmethyl analogs...
Figure 6: Tool compounds used by Pluschke and co-workers for elucidating the molecular targets of mycolactone...
Figure 7: Synthetic strategies towards the extended mycolactone core. A) General strategies. B) Kishi’s appro...
Scheme 1: Kishi’s 1st generation approach towards the extended core structure of mycolactones. Reagents and c...
Scheme 2: Kishi’s 2nd generation approach towards the extended core structure of mycolactones. Reagents and c...
Scheme 3: Kishi’s 3rd generation approach towards the extended core structure of mycolactones. Reagents and c...
Scheme 4: Negishi’s synthesis of the extended core structure of mycolactones. Reagents and conditions: a) (i) ...
Scheme 5: Burkart’s (incomplete) 1st generation approach towards the extended core structure of mycolactones....
Scheme 6: Burkart’s (incomplete) 1st, 2nd and 3rd generation approach towards the extended mycolactone core s...
Scheme 7: Altmann’s synthesis of alkyl iodide 91. Reagents and conditions: a) (i) PMB-trichloroacetimidate, T...
Scheme 8: Final steps of Altmann’s synthesis of the extended core structure of mycolactones. Reagents and con...
Scheme 9: Basic principles of the Aggarwal lithiation–borylation homologation process [185,186].
Scheme 10: Aggarwal’s synthesis of the C1–C11 fragment of the mycolactone core. Reagents and conditions: a) Cl...
Scheme 11: Aggarwal’s synthesis of the linear C1–C20 fragment of the mycolactone core. Reagents and conditions...
Figure 8: Synthetic strategies towards the mycolactone A/B lower side chain.
Scheme 12: Gurjar and Cherian’s synthesis of the C1’–C8’ fragment of the mycolactone A/B pentaenoate side chai...
Scheme 13: Gurjar and Cherian’s synthesis of the benzyl-protected mycolactone A/B pentaenoate side chain. Reag...
Scheme 14: Kishi’s synthesis of model compounds for elucidating the stereochemistry of the C7’–C16’ fragment o...
Scheme 15: Kishi’s synthesis of the mycolactone A/B pentaenoate side chain. (a) (i) NaH, (EtO)2P(O)CH2CO2Et, T...
Scheme 16: Feringa and Minnaard's incomplete synthesis of mycolactone A/B pentaenoate side chain. Reagents and...
Scheme 17: Altmann’s approach towards the mycolactone A/B pentaenoate side chain. Reagents and conditions: a) ...
Scheme 18: Negishi’s access to the C1’–C7’ fragment of mycolactone A. Reagents and conditions: a) (i) n-BuLi, ...
Scheme 19: Negishi’s approach to the C1’–C7’ fragment of mycolactone B. Reagents and conditions: a) (i) DIBAL-...
Scheme 20: Negishi’s synthesis of the C8’–C16’ fragment of mycolactone A/B. Reagents and conditions: a) 142, BF...
Scheme 21: Negishi’s assembly of the mycolactone A and B pentaenoate side chains. Reagents and conditions: a) ...
Scheme 22: Blanchard’s approach to the mycolactone A/B pentaenoate side chain. a) (i) Ph3P=C(Me)COOEt, CH2Cl2,...
Scheme 23: Kishi’s approach to the mycolactone C pentaenoate side chain exemplified for the 13’R,15’S-isomer 1...
Scheme 24: Altmann’s (unpublished) synthesis of the mycolactone C pentaenoate side chain. Reagents and conditi...
Scheme 25: Blanchard’s synthesis of the mycolactone C pentaenoate side chain. Reagents and conditions: a) (i) ...
Scheme 26: Kishi’s synthesis of the tetraenoate side chain of mycolactone F exemplified by enantiomer 165. Rea...
Scheme 27: Kishi’s synthesis of the mycolactone E tetraenoate side chain. Reagents and conditions: a) (i) CH2=...
Scheme 28: Wang and Dai’s synthesis of the mycolactone E tetraenoate side chain. Reagents and conditions: a) (...
Scheme 29: Kishi’s synthesis of the dithiane-protected tetraenoate side chain of the minor oxo-metabolite of m...
Scheme 30: Kishi’s synthesis of the mycolactone S1 and S2 pentaenoate side chains. Reagents and conditions: a)...
Scheme 31: Kishi’s 1st generation and Altmann’s total synthesis of mycolactone A/B (1a,b) and Negishi’s select...
Scheme 32: Kishi’s 2nd generation total synthesis of mycolactone A/B (1a,b). Reagents and conditions: a) 2,4,6...
Scheme 33: Blanchard’s synthesis of the 8-desmethylmycolactone core. Reagents and conditions: a) (i) TsCl, TEA...
Scheme 34: Altmann’s (partially unpublished) synthesis of the C20-hydroxylated mycolactone core. Reagents and ...
Scheme 35: Altmann’s and Blanchard’s approaches towards the 11-isopropyl-8-desmethylmycolactone core. Reagents...
Scheme 36: Blanchard’s synthesis of the saturated variant of the C11-isopropyl-8-desmethylmycolactone core. Re...
Scheme 37: Structure elucidation of photo-mycolactones generated from tetraenoate 224.
Scheme 38: Kishi’s synthesis of the linear precursor of the photo-mycolactone B1 lower side chain. Reagents an...
Scheme 39: Kishi’s synthesis of the photo-mycolactone B1 lower side chain. Reagents and conditions: a) LiTMP, ...
Scheme 40: Kishi’s synthesis of a stabilized lower mycolactone side chain. Reagents and conditions: a) (i) TBD...
Scheme 41: Blanchard’s variation of the C12’,C13’,C15’ stereocluster. Reagents and conditions: a) (i) DIBAL-H,...
Scheme 42: Blanchard’s synthesis of aromatic mycolactone polyenoate side chain analogs. Reagents and condition...
Scheme 43: Small’s partial synthesis of a BODIPY-labeled mycolactone derivative and Demangel’s partial synthes...
Scheme 44: Blanchard’s synthesis of the BODIPY-labeled 8-desmethylmycolactones. Reagents and conditions: a) (i...
Scheme 45: Altmann’s synthesis of biotinylated mycolactones. Reagents and conditions: a) (i) CDI, THF, rt, 2 d...
Figure 9: Kishi’s elongated n-butyl carbamoyl mycolactone A/B analog.
Graphical Abstract
Scheme 1: Germacrene A (1) and its Cope rearrangement to β-elemene (2).
Figure 1: In vitro terpene synthase activity of the investigated recombinant enzyme from C. pinensis, showing...
Scheme 2: Product obtained from the diterpene synthase from C. pinensis. (A) Structure of (1R,3E,7E,11S,12S)-...
Figure 2: Determination of the absolute configuration of 3. (A) Partial HSQC spectrum of unlabelled 3 showing...
Figure 3: Determination of the absolute configuration of 3. (A) Partial HSQC spectrum of unlabelled 3 showing...
Figure 4: Assignment of H6α and H6β of 3. (A) Partial HSQC spectrum of unlabelled 3 showing the region for C6...
Figure 5: Partial 13C NMR spectra of A) unlabeled 3, B) (13C1)-3 arising from incubation of HdS and GGPPS wit...
Figure 6: Transient expression of 18-hydroxydolabella-3,7-diene synthase (HdS) in Nicotiana benthamiana. Tota...
Graphical Abstract
Scheme 1: The structures of clethramycin, mediomycins and related linear polyenes.
Scheme 2: The biosynthetic gene clusters for mediomycin (med) from Streptomyces mediocidicus and clethramycin...
Figure 1: HPLC–UV–MS analysis of polyenes. A) LC–UV (360 nm) trace of mycelium methanol extract from DSM4137 ...
Figure 2: HPLC–UV–MS analysis of polyenes from DSM4137 wild type and mutants. A) LC–UV (360 nm) trace of myce...
Scheme 3: The parallel pathways for the biosynthesis of mediomycin A.
Figure 3: HPLC–UV–MS analysis of in vitro assays with amidinohydrolase Medi4948 and sulfotransferase Slf from ...