A convergent and stereoselective total synthesis of (−)-crispine A, (−)-benzo[a]quinolizidine and (−)-salsolidine

Reddy, Pedavenkatagari Narayana; Reddy, B. Jagannadha; Reddy, B. V. Subba

doi:10.1016/j.tetlet.2013.05.132

Cited by 37 publications

(25 citation statements)

References 39 publications

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“…The hydrogenation of the olefin moiety, simultaneous deprotection of the Cbz group on the nitrogen atom of the THIQ framework and ring closure was achieved smoothly by hydrogenation (1 atm) over 10% Pd/C in EtOAc to provide the desired lactam (±)-9 in 85%. Reduction of lactam (±)-9 with LiAlH 4 in THF according to Reddy and co-workers (Reddy et al, 2013) afforded (±)-benzo[a]quinolizidine (10) in 77%, whose spectral data were in good agreement with those reported in the literature (Williams et al, 2005;Szawkalo et al, 2007;Reddy et al, 2013;Talk et al, 2016).…”

Section: A Concise and Efficient 3-step Total Synthesis Of (±)-Benzo[a]quinolizidinesupporting

confidence: 83%

Direct and Efficient C(sp3)–H Functionalization of N-Acyl/Sulfonyl Tetrahydroisoquinolines (THIQs) With Electron-Rich Nucleophiles via 2,3-Dichloro-5,6-Dicyano-1,4-Benzoquinone (DDQ) Oxidation

Kim

Baek

et al. 2020

Front. Chem.

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A highly efficient metal-free oxidative direct C(sp 3 )–H functionalization of N -acyl/sulfonyl 1,2,3,4-tetrahydroisoquinolines (THIQs) with a wide range of electron-rich nucleophiles was accomplished under mild conditions through oxidation with DDQ and subsequent trapping of the resulting reactive and stable N -acyl/sulfonyl iminium ions. The synthetic utility of this method was illustrated by a concise and efficient total synthesis of (±)-benzo[ a ]quinolizidine ( 10 ) in 3 steps from the known N -Cbz 1,2,3,4-THIQ 4b .

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Section: A Concise and Efficient 3-step Total Synthesis Of (±)-Benzo[a]quinolizidinesupporting

confidence: 83%

Direct and Efficient C(sp3)–H Functionalization of N-Acyl/Sulfonyl Tetrahydroisoquinolines (THIQs) With Electron-Rich Nucleophiles via 2,3-Dichloro-5,6-Dicyano-1,4-Benzoquinone (DDQ) Oxidation

Kim

Baek

et al. 2020

Front. Chem.

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“…The allylated product was obtained in 80% yield as 9:1 mixture of diastereoisomers, and the major diastereoisomer was separated from the mixture and cyclized to give tetra-hydroisoquinoline 217 (see above, Scheme 53). The formation of the 5-membered ring to produce target (−)-crispine A (223) was accomplished in six additional steps which comprise removal of the sulfinyl group and subsequent N-Boc protection to give 221, hydroboration-oxidation to produce terminal alcohol derivative 222, and formation of the mesylate, removal of the Boc group, and final cyclization (Scheme 54) [150].…”

Section: Initial Stereocontrol By Allylation Of Sulfinyl Iminesmentioning

confidence: 99%

N-tert-Butanesulfinyl imines in the asymmetric synthesis of nitrogen-containing heterocycles

Mendes¹,

Costa²,

Yus³

et al. 2021

Beilstein J. Org. Chem.

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The synthesis of nitrogen-containing heterocycles, including natural alkaloids and other compounds presenting different types of biological activities have proved to be successful employing chiral sulfinyl imines derived from tert-butanesulfinamide. These imines are versatile chiral auxiliaries and have been extensively used as eletrophiles in a wide range of reactions. The electron-withdrawing sulfinyl group facilitates the nucleophilic addition of organometallic compounds to the iminic carbon with high diastereoisomeric excess and the free amines obtained after an easy removal of the tert-butanesulfinyl group can be transformed into enantioenriched nitrogen-containing heterocycles. The goal of this review is to the highlight enantioselective syntheses of heterocycles involving the use of chiral N-tert-butanesulfinyl imines as reaction intermediates, including the synthesis of several natural products. The synthesis of nitrogen-containing heterocycles in which the nitrogen atom is not provided by the chiral imine will not be considered in this review. The sections are organized according to the size of the heterocycles. The present work will comprehensively cover the most pertinent contributions to this research area from 2012 to 2020. We regret in advance that some contributions are excluded in order to maintain a concise format.

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“…Reddy's group also explored enantiopure tert-butanesulnamide in the asymmetric synthesis of (À)-crispine A, (À)-salsolidine and (À)-benzo[a]quinolizidine. 31 The synthetic route towards (À)-salsolidine 126 started from the aforementioned sulnimine 118 derived from 2-(3,4-dimethoxyphenyl)ethanol. Subjecting 118 to Grignard reaction provided methyl sulnamide 124 with good diastereoselectivity (dr ¼ 95 : 5) which in turn was cyclized under basic conditions to afford the cyclized…”

Section: Benzofused Piperidine Ringmentioning

confidence: 99%

Applications oftert-butanesulfinamide in the synthesis of N-heterocyclesviasulfinimines

et al. 2020

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A convergent and stereoselective total synthesis of (−)-crispine A, (−)-benzo[a]quinolizidine and (−)-salsolidine

Cited by 37 publications

References 39 publications

Direct and Efficient C(sp3)–H Functionalization of N-Acyl/Sulfonyl Tetrahydroisoquinolines (THIQs) With Electron-Rich Nucleophiles via 2,3-Dichloro-5,6-Dicyano-1,4-Benzoquinone (DDQ) Oxidation

Direct and Efficient C(sp3)–H Functionalization of N-Acyl/Sulfonyl Tetrahydroisoquinolines (THIQs) With Electron-Rich Nucleophiles via 2,3-Dichloro-5,6-Dicyano-1,4-Benzoquinone (DDQ) Oxidation

N-tert-Butanesulfinyl imines in the asymmetric synthesis of nitrogen-containing heterocycles

Applications oftert-butanesulfinamide in the synthesis of N-heterocyclesviasulfinimines

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