Stereocontrolled formation of cis and trans ring junctions in hydrindane and decalin systems by palladium-catalyzed regioselective and stereospecific hydrogenolysis of allylic formates

Mandai, Tadakatsu; Matsumoto, T.; Kawada, Mikio; Tsuji, Jiro

doi:10.1021/jo00031a005

Cited by 79 publications

(22 citation statements)

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“…Palladium-catalyzed reductive transposition of the allylic carbonate then gave trans -hydrindene ketal 17 in 77% yield. 16 Cyclopropanation of trisubstituted alkene 17 with diethylzinc and chloroiodomethane, 17 followed by acidic workup, produced ketone 18 . Subjection of cyclopropane 18 to hydrogenolysis conditions, followed by oxidation of the resulting secondary alcohol, delivered trans -hydrindanone 13 in 88% yield over two steps.…”

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confidence: 99%

Total Synthesis of (−)-Chromodorolide B

2016

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Total Synthesis of (−)-Chromodorolide B

2016

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“…For example, hydrogenation of compound 38a in the presence of PtO 2 furnished selectively the trans-disubstituted piperidine 39, but the use of Pd/C gave also the 2-substituted piperidine 40 as a minor product (70/30 NMR ratio). Then, heterogeneous hydrogenation carried out with ammonium formate at 80 • C with a catalytic amount of Pd/C [46] provided a 60/40 mixture of piperidines 39 (minor) and 40 (major). A plausible reason of this reactivity involves the oxidative addition of palladium or platinum to the enecarbamate moiety, due to the known capacity of these metals to generate π-allyl complexes [47].…”

Section: Reductive Elaboration Of 142-dioxazinesmentioning

confidence: 99%

Nitroso Diels-Alder Cycloadducts Derived From N-Acyl-1,2-dihydropyridines as a New Platform to Molecular Diversity

2020

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This review focuses upon the use of nitroso Diels–Alder reactions as a structural complexity generating reaction that has been so far a quite scarcely treated topic, despite its potential. In particular, the use of N-acyl-1,2-dihydropyridines as a non-symmetrical diene component in nitroso Diels–Alder reactions encompasses an initial diversification of pathways giving rise to different cycloadducts (direct and inverse). Selective elaborations of these cycloadducts, basically using a reagent-based approach, deliver a discrete number of structurally diverse compounds, including some original heterobicyclic scaffolds and functionalized heterocycles. This forward synthetic planning allowed the individuation of a new biologically active compound based on a novel oxadiaza-bicyclic-[3.3.1]-nonene scaffold which is still under preclinical evaluation.

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“…Furthermore, if the alcoholic group is to be oxidized later in the synthetic scheme, the formylated alcoholic does not need to be deprotected, in which case direct oxidation under Oppenauer conditions can be used [6]. In addition, formate esters are useful synthetic reagents and intermediates [7][8][9].…”

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confidence: 99%

Synthesis of Betulin Diformate and Allobetulin Formate Directly From Outer Birch Bark

Arrous

Boudebouz

Бакибаев

2019

JCPRM

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One of the promising directions of birch bark utilization is its extractive treatment with obtaining a number of valuable chemical components among which the most relevant is betulin. As a rule, the methods of betulin esters are multistage and based on classical reactions of betulin acylation; betulin should be preliminarily extracted from birch bark. The purpose of the present research was synthesis of the betulin diformate and allobetulin formate directly from the birch bark without a separate stage of the betulin preparation. The external layer of the bark of birch, Betula pendula Roth was ground to particle size of 10–20 mm and used as the raw material. The method is based on combined extraction of betulin from outer birch bark and its formylation with formic acid at reflux for 16 hours. During the treatment of birch bark with formic acid, along with betulin extraction into solution, its formylation into betulin diformate and allobetulin formate occurs. The yield of the formation of betulin diformate and allobetulin formate of the mass of acylated upper bark (a.u.b.) was 40 and 10%, respectively. The first fraction of betulin diformate was obtained from the resulted solution by evaporating 3/4 of the solution and poured it in water to form beige precipitate, whereas the second fraction was extracted by treating the resulted birch bark by acetone followed by evaporation. However, the allobetulin formate was formed from the second treatment of resulted birch bark by chloroforrm followed by evaporation. Betulin diformate was found to be the main component of this extraction, and it was recrystallized from ethyl alcohol to afford beige powder, and its melting point is 165 °C. The structures of betulin diformate and allobetulin formate are confirmed by 1H NMR, 13C NMR, and FTIR spectroscopy.

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Stereocontrolled formation of cis and trans ring junctions in hydrindane and decalin systems by palladium-catalyzed regioselective and stereospecific hydrogenolysis of allylic formates

Cited by 79 publications

References 0 publications

Total Synthesis of (−)-Chromodorolide B

Total Synthesis of (−)-Chromodorolide B

Nitroso Diels-Alder Cycloadducts Derived From N-Acyl-1,2-dihydropyridines as a New Platform to Molecular Diversity

Synthesis of Betulin Diformate and Allobetulin Formate Directly From Outer Birch Bark

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