Tandem Processes Identified from Reaction Screening: Nucleophilic Addition to Aryl <i>N</i>-Phosphinylimines Employing La(III)-TFAA Activation

Kinoshita, Hidenori; Ingham, Oscar J.; Ong, Winnie W.; Beeler, Aaron B.; Porco, John A.

doi:10.1021/ja100346w

Cited by 41 publications

(13 citation statements)

References 49 publications

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“…All products 23b–k were obtained as single isomers. Relative stereochemistry at C5, C6, and C7 could be assigned as 5,6- cis and 6,7- trans on the basis of extensive NOE studies. , …”

Section: Resultsmentioning

confidence: 99%

Stereoselective Convergent Synthesis of Tetrahydro-5H-benzo[c]fluorene via Nine-Membered Ring-Closing Metathesis and Transannular Acid-Mediated Cyclization/Nucleophilic Addition

Lekky¹,

Ruengsatra²,

Ruchirawat

et al. 2019

J. Org. Chem.

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The diene methyl ethers or acetates, constructed from the Li–Br exchange/addition reactions of 2-vinylbenzaldehydes and 2-(but-3-en-1-yl)bromoarenes followed by etherification or acetylation of the corresponding alcohols, smoothly underwent the ring-closing metathesis (RCM) by using Hoveyda–Grubbs II as a catalyst to provide the corresponding benzannulated (Z)-cyclononenes as single products in good yields (up to 75%). The ensuing one-pot acid-mediated transannular cyclization/nucleophilic addition at C7 furnished the corresponding tetrahydro-5H-benzo[c]fluorenes as single stereoisomers with the exclusive cis stereochemistry at the ring junction (C5–C6) and trans at the site of nucleophilic attack (C6–C7) on the three contiguous stereogenic centers in good to excellent yield (up to 94%). The developed strategy was general; the reaction conditions were compatible with hydride, azide, and electron-rich aromatics as nucleophiles. In addition, various methoxylated benzannulated cyclononene acetates could be employed as substrates. Thus, tetrahydro-5H-benzo[c]fluorenes could be prepared in four steps from appropriately substituted bromoarenes and benzaldehydes in good yields (up to 56%) with excellent stereo- and regio-control.

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“…All products 23b–k were obtained as single isomers. Relative stereochemistry at C5, C6, and C7 could be assigned as 5,6- cis and 6,7- trans on the basis of extensive NOE studies. , …”

Section: Resultsmentioning

confidence: 99%

Stereoselective Convergent Synthesis of Tetrahydro-5H-benzo[c]fluorene via Nine-Membered Ring-Closing Metathesis and Transannular Acid-Mediated Cyclization/Nucleophilic Addition

Lekky¹,

Ruengsatra²,

Ruchirawat

et al. 2019

J. Org. Chem.

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“…[46] The tentative structure assignment is based on spectral and analytical data. That is, the IR spectrum shows absorptions for the strained carbonyl and imine at 1758 and 1721 cm À1 , respectively, which may seem reasonable when compared with absorptions at 1760 and 1670 cm À1 for the analogous unit in 7 (Scheme 2) and in the light of imine absorptions in N-phosphinyl imines in the 1680-1690 cm À1 range, [47] i.e. at higher wavenumber than ordinary imines (1610-1635 cm À1 ).…”

Section: Synthesis Of 4-iminocyclobutenonesmentioning

confidence: 57%

New Syntheses and Ring Expansion Reactions of Cyclobutenimines

et al. 2010

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Two routes are reported for the synthesis of iminocyclobutenones having N-(het)aryl substitution: an addition/substitution sequence starting with cyclobutenediones and an aza-Wittig method. A new synthetic route to N-alkyl derivatives is also presented. This involves O-alkylation of 3-alkylamino-1,2-cyclobutenediones using Meerwein's reagent and subsequent deprotonation under non-hydrolytic conditions. Lithium organyls were found to add to the remaining carbonyl group. The resulting tertiary alcohols undergo ring enlargement on heating in xylene to give 4-aminophenols, 4-amino-1-naphthols, or cyclopenta-annulated quinolines from 4-vinyl, 4-aryl, and 4-alkynyl derivatives, respectively.

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“…For the major isomer. 1 H NMR (500 MHz, CDCl3) δ 7.82 (d, J = 8.0 Hz, 2H), 7.33 (d, J = 8.0 Hz, 2H), 7.26 (d, J = 7.9 Hz, 2H), 7.17 (d, J = 8.1 Hz, 2H), 7.06 (d, J = 7.9 Hz, 2H), 6.86 (d, J = 8.1 Hz, 2H), 5.41 (d, J = 4.0 Hz, 1H), 4.02 -3.98 (m, 1H), 3.12 (m, 1H), 2.66 (tt, J = 12.5, 3.2 Hz, 1H), 2.46 (s, 3H), 2.39 (d, J=13.0, 1H) 2.35 (s, 3H), 2.29 (s,3H),1.78 (td,J = 13.5,5.3 Hz,1H),1.55 (s,1H) 1.44 (ddd,J = 25.6,12.8,4.5 Hz, 1H); 13 C NMR (125 MHz,CDCl3) δ 143.1,142.2,138.7,136.6,136.1,135.4,129.8,129.5,129.2,127.1,126.7,126.4,55.2,41.8,36.0,34.2,31.8,21.5,21.0; HRMS (ESI) calcd for C26H30NO2S [M+Na]: 442.1811, Found 442.1809. Synthesis of 2,4-di-m-tolyl-1-tosylpiperidine (5c) was followed general procedure and percentage yield of reaction between DTD and 3methylstyrene was 90% with 72: 28 cis: dr ratio.…”

Section: Template For Synthesis Thiemementioning

confidence: 99%

“…18 While intramolecular aza-Prins reactions are well documented 6c 19 and widely applicable in syntheses, 20 catalytic intermolecular aza-Prins processes are highly challenging due to the insufficient nucleophilicity of the iminium species. 6c 19e 21 Using an InCl 3 -catalyzed intermolecular aza-Prins reaction with formaldimines as highly reactive reagents, this catalytic [2+2+2] system is capable of employing alkenes and allenes with a broad scope of electronic and steric properties.…”

mentioning

confidence: 99%

Catalytic Amidomethylative [2+2+2] Cycloaddition of Formaldimine and Styrenes toward N-Heterocycles

Lakmal¹,

Istre²,

Qian³

et al. 2021

Synthesis

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Chemo-switchable catalytic [2+2+2] cycloaddition of alkenes with formaldimines has been reported. Bis(tosylamido)methane (BTM) and 1,2-ditosyl-1,2-diazetidine (DTD), two bench-stable precursors for highly reactive tosylformaldimine, have been identified to be effective. BTM worked as a selective releaser of the formaldimine for catalytic [2+2+2] reactions toward hexahydropyrimidine products via a presumable “imine-alkene-imine” addition. A unique catalytic retro-[2+2] reaction of DTD was used and has enabled a proposed “imine-alkene-alkene” pathway with high chemoselectivity for the synthesis of 2,4-diarylpyperidine derivatives. The two alternative processes were catalyzed by simple and environmentally benign catalysts InCl3 and FeBr2, respectively.

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Tandem Processes Identified from Reaction Screening: Nucleophilic Addition to Aryl N-Phosphinylimines Employing La(III)-TFAA Activation

Cited by 41 publications

References 49 publications

Stereoselective Convergent Synthesis of Tetrahydro-5H-benzo[c]fluorene via Nine-Membered Ring-Closing Metathesis and Transannular Acid-Mediated Cyclization/Nucleophilic Addition

Stereoselective Convergent Synthesis of Tetrahydro-5H-benzo[c]fluorene via Nine-Membered Ring-Closing Metathesis and Transannular Acid-Mediated Cyclization/Nucleophilic Addition

New Syntheses and Ring Expansion Reactions of Cyclobutenimines

Catalytic Amidomethylative [2+2+2] Cycloaddition of Formaldimine and Styrenes toward N-Heterocycles

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