Total synthesis refutes the postulated structure of leucogenenol

Keywords: Alcohols / Cyclic ethers / Cyclizations / Entropy / Medium-sized rings / Synthetic methods 7-Octen-1-ols substituted in the sp 3 −sp 3 carbon chain with carbocyclic (phenyl and cyclopropane) and heterocyclic (epoxide and dioxolane) moieties were prepared and their cyclizations in the presence of bis(collidine)iodonium(I) and -bromonium(I) hexafluorophosphates as electrophiles were studied. Oxocanes were obtained in modest to good yields when a rigid cyclic moiety (cyclopropane or phenyl) was present in the chain, while yields of cyclizations were lower if

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“…Subsequent reduction with hydrogen (1 atm) in the presence of Lindlar catalyst in acetone gave the alcohol 22 [28] (90%).…”

Section: -(2-vinylphenyl)butan-1-ol (2)supporting

confidence: 50%

“…(2E)-Octa-2,7-dien-1-ol (23): Lithium aluminum hydride reduction of the acetylenic alcohol 21 in THF gave the alcohol 23 [28] (80%).…”

Section: -(2-vinylphenyl)butan-1-ol (2)supporting

confidence: 49%

Preparation of Oxocanes by Electrophilic Cyclizations of Unsaturated Alcohols in the Presence of Bis(collidine)halonium(I) Hexafluorophosphates

et al. 2003

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“…145 (30) 145 (29) 145 (28) 145 (30) 145 (25) 145 (21) 145 (16) 145 (19) 145 (23) 145 (26) 145 (16) 145 (14) 137 (39) 137 (8) 137 (6) 137 (7) 137 (9) 137 (10) 137 (14) 137 (16) 137 (16) 137 (15) 137 (13) 137 (18) 137 (20) G 135 (10) 135 (4) 135 (2) 135 (3) 135 (3) 135 (3) -135 (6) 135 (6) 135 (18) 135 (7) 135 (7) 135 (6) 134 (13) 134 (6) 134 (6) 134 (6) 134 (6) 134 (5) -134 (5) 134 (5) 134 (5) 134 (4) 134 (4) 134 (4) 131 (27) 131 (2) 131 (3) 131 (3) 131 (2) 131 (3) 131 (9) 131 (2) 131 (4) 131 (2) 131 (1) 131 (2) 131 …”

Section: Resultsunclassified

Electron ionization mass spectrometry of curcumin analogues: an olefin metathesis reaction in the fragmentation of radical cations

1998

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The natural compound curcumin, used in cosmetics, traditional medicines and as a spice in food, is known as a multi‐factorial anti‐inflammatory agent. To study the anti‐inflammatory activity of curcumin derivatives, 24 analogues were synthesized and their structures were confirmed by 1H NMR and electron ionization (EI) mass spectrometry. Most signals in the EI mass spectra can be attributed to commonly known fragmentations, but the formation of ring‐substituted 1,2‐diphenylethene (stilbene)‐type radical cations, observed in the spectra of all compounds investigated and resulting in the base peak for some compounds, requires a peculiar rearrangement. Metastable ion spectra and 13C labelling studies show that the stilbene‐type ions are formed directly from the molecular ions and contain the two original aryl groups and the 1 and 7 carbon atoms of the olefinic system. It is proposed that the formation of stilbene‐type ions results from an intramolecular olefin metathesis reaction; this suggestion is supported by semi‐empirical (MNDO/PM3) calculations. © 1998 John Wiley & Sons, Ltd.

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“…4 6.1, J 4 . 5 2.7 Hz, 4-H), 6.9br (1 H, NH), 6.78 (1 H, dd, J6.7 2.6, J5.6 0.9 Hz, 6-H), 6.20 (1 H,d,J6,7 2.6 Hz,6.12 (1 H, d, J 3 . 4 6.1 Hz, 3-H), 3.92 (1 H, dd, J4,5 2.7, J5,6 0.9 Hz, 5-H), and 2.00 (3 H, s, CH3).…”

Section: Resultsmentioning

confidence: 99%

“…(MeOH) 274 and 230 nm (E 4 900 and 10 000) whilst no absorption band maximum was detectable in the 300-350 nm region; 6 , (CDC13) 8.7br (1 H,NH),7.72 (1 H,dd,J3,4 5.6,J4,5 2.8 Hz, (5 H, m, Ph), 6.1 (1 H, d, J5,a 1.0 Hz, 6-H), 6.0 (1 H, dd, J3,4 5.6, Jl,3 0.9 Hz, 3-H), 3.90 (1 H, m, J4,5 2.8, J1.5 2.8, J5. 6 1.0 Hz, 5-H), 3.63 (1 H, dd, J1.5 2.8, J1,3 0.9 Hz, 1 -H). 4).…”

Section: Resultsmentioning

confidence: 99%

Chiral laser photochemistry: photoresolution accompanying photoisomerization of (±)-1-acetyl(benzoyl)aminobicyclo[3.2.0]hepta-3,6-dien-2-one to optically active 7-isomers. A photochemical procedure for chirality enhancement of (–)-(1S,5S)-7-acetylaminobicyclo[3.2.0]hepta-3,6-dien-2-one

Cavazza¹,

Morganti²,

Zandomeneghi³

1984

J. Chem. Soc., Perkin Trans. 2

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Racemisches Aminoketon (Ia), das durch Photoisomerisierung mit linearpolarisiertem Licht aus dem entsprechenden Tropon hergestellt wird (Ausb. 32%), ergibt nach seiner Bestrahlung mit links‐circularpolarisiertem (lcp) UV‐Licht nach 36proz. Umsatz stereospezifisch ein Gemisch aus (Ia) und seinem (‐ )‐(lS,5 R)‐Enantiomer (IIa) (Gemischanteil 64%) mit dem (‐ )‐(lS,5S)‐Isomer (IIIa) (36%).

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Total synthesis refutes the postulated structure of leucogenenol

Cited by 17 publications

References 0 publications

Preparation of Oxocanes by Electrophilic Cyclizations of Unsaturated Alcohols in the Presence of Bis(collidine)halonium(I) Hexafluorophosphates

Preparation of Oxocanes by Electrophilic Cyclizations of Unsaturated Alcohols in the Presence of Bis(collidine)halonium(I) Hexafluorophosphates

Electron ionization mass spectrometry of curcumin analogues: an olefin metathesis reaction in the fragmentation of radical cations

Chiral laser photochemistry: photoresolution accompanying photoisomerization of (±)-1-acetyl(benzoyl)aminobicyclo[3.2.0]hepta-3,6-dien-2-one to optically active 7-isomers. A photochemical procedure for chirality enhancement of (–)-(1S,5S)-7-acetylaminobicyclo[3.2.0]hepta-3,6-dien-2-one

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