Stereoselective Construction of the Highly Congested Tricyclic Core Structure in Leucosceptroid H

Sun, Peng; Zhang, Chi; Qiao, Tianjiao; Ao, Junli; Wu, Shuming; Liang, Guangxin

doi:10.1021/acs.orglett.0c01672

Cited by 3 publications

(2 citation statements)

References 31 publications

(20 reference statements)

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“…The combined organic extracts were washed with brine (5 mL) and dried over Na 2 SO 4 . The solvent was removed under vacuum, and residue was purified by a flash column chromatography on silica gel (petroleum ether/ethyl acetate = 15:1) to give product 47 (239.0 mg, 0.47 mmol, 84%, single isomer) as a white solid . Data for 47 : R f 0.78 (4:1, petroleum ether:ethyl acetate); mp = 156–158 °C; 1 H NMR (400 MHz, CDCl 3 ) δ 5.80–5.70 (m, 1H), 5.42 (s, 1H), 5.18–5.10 (m, 2H), 5.06–5.03 (m, 1H), 4.67 (s, 2H), 4.34 (s, 1H), 3.92 (s, 1H), 3.81 (d, J = 11.0 Hz, 1H), 3.57 (d, J = 11.0 Hz, 1H), 3.35 (s, 3H), 3.22 (d, J = 9.9 Hz, 1H), 2.33–2.26 (m, 1H), 2.21–2.16 (m, 1H), 2.12–2.03 (m, 1H), 1.83 (s, 3H), 1.70 (s, 3H), 1.24 (s, 1H), 1.00 (d, J = 7.6 Hz, 3H), 0.27 (s, 9H); 13 C{ 1 H} NMR (100 MHz, CDCl 3 ) δ 225.4, 173.6, 143.9, 136.8, 123.3, 117.0, 83.6, 83.1, 79.8, 77.3, 76.9, 56.6, 52.8, 52.5, 43.1, 38.0, 35.3, 21.7, 20.4, 1.8; IR (thin film) υ max 3463, 3441, 2955, 1778, 1636, 1279, 1255, 1069, 1029, 916, 848, 756, 712, 668, 534, 493,451; HRMS (ESI) m / z : [M + H] + calcd for C 22 H 38 BrO 6 Si: 505.1616, found: 505.1610.…”

Section: Methodsmentioning

confidence: 99%

“…To date, no total syntheses of leucosceptroids bearing the α-C11 hydroxyl group, such as leucosceptroid F ( 4 ) and H ( 3 ), have been reported. Recently, we have demonstrated construction of the highly congested [5,6,5] tricyclic framework of leucosceptroid H . Herein, we report our efforts on a synthetic solution to access either the α- or β-C11 hydroxyl group selectively for a collective total synthesis of the leucosceptroid family of natural products.…”

Section: Introductionmentioning

confidence: 99%

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Synthetic Studies toward Leucosceptroid Family of Natural Products

Sun

Qiao

et al. 2021

J. Org. Chem.

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Leucosceptroids are sesterterpenoids with potent antifeedant and antifungal activities. In this paper, efforts on two synthetic strategies toward stereoselective total synthesis of the leucosceptroid family of natural products are reported. Intramolecular addition cyclization strategy could lead to a stereochemically mismatched core structure, while intermolecular addition/ring-closing metathesis cyclization strategy successfully furnished an advanced common intermediate bearing eight contiguous stereogenic centers, including three tetra-substituted ones, which fully matches all the stereochemistry on the tricyclic framework in leucosceptroid H. Late-stage transformation of this intermediate to leucosceptroid H encountered difficulty in oxidizing the secondary hydroxyl group to a carbonyl group in the target. Instead of the desired oxidation, an interesting tricyclic spiral product originating from a C−C bond cleavage was observed.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthetic Studies toward Leucosceptroid Family of Natural Products

Sun

Qiao

et al. 2021

J. Org. Chem.

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Stereo‐Controlled Synthesis of Vicinal Tertiary Carbinols: Application in the Synthesis of a Diol Substructure of Zaragozic Acid, Pactamycin and Ryanodol

Kim,

Puthukanoori,

Martha

et al. 2023

Chemistry A European J

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A novel and flexible approach for the stereo‐controlled synthesis of vicinal tertiary carbinols is reported. The developed strategy featured a highly diastereoselective singlet‐oxygen (O21) [4+2] cycloaddition of rationally designed cyclohexadienones (derived from oxidative dearomatization of the corresponding carboxylic‐acid appended phenol precursors), followed by programmed “O−O” and “C−C” bond cleavage. In doing so, a highly functionalized and versatile intermediate was identified and prepared in synthetically useful quantity as a plausible precursor to access a variety of designed and naturally occurring vicinal tertiary carbinol containing compounds. Most notably, the developed strategy was successfully applied in the stereo‐controlled synthesis of advanced core structures of zaragozic acid, pactamycin and ryanodol.

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DBU- and DABCO-Promoted Selective Access to 2,5-Diarylnitrobenzoates and Cyclohexenones via One-Pot Reactions

Samanta¹,

Rathor²,

Majee³

2022

Synlett

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Remarkable organobase-controlled selective synthesis of a wide breadth of valuable 2,5-diaryl-4-nitrobenzoates and 1-hydroxy-4-oxocyclohexencarboxylates bearing a tetra-substituted stereogenic carbon is reported. This one-pot cyclization reaction operates between a bunch of 3-nitroallylarenes and β,γ-unsaturated α-ketocarbonyls by carefully choosing DBU or DABCO as an organobase under aerobic conditions. Notably, as a nucleophilic base, DABCO favours the Nef-reaction over the dehydration-aerial oxidation process, aiming for unexpected cyclohexanone architectures. Moreover, this operationally simple technique holds a few positive qualities: good yields with diastereoselectivities (dr≤91:9), broad substrate scope, no added oxidant, excellent functional group compatibility, 100% carbon-economical etc. Furthermore, the obtained 4-nitrobenzoate framework has been utilized for the synthesis of a range of valuable compounds such as 2-phenylcarbazole-3-carboxylate, 3-bromoaniline derivative, 2,5-diphenylbenzoic acid etc.

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Stereoselective Construction of the Highly Congested Tricyclic Core Structure in Leucosceptroid H

Cited by 3 publications

References 31 publications

Synthetic Studies toward Leucosceptroid Family of Natural Products

Synthetic Studies toward Leucosceptroid Family of Natural Products

Stereo‐Controlled Synthesis of Vicinal Tertiary Carbinols: Application in the Synthesis of a Diol Substructure of Zaragozic Acid, Pactamycin and Ryanodol

DBU- and DABCO-Promoted Selective Access to 2,5-Diarylnitrobenzoates and Cyclohexenones via One-Pot Reactions

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