Alkylindan synthesis via an intermolecular [3+2] cycloaddition between unactivated alkenes and in situ generated p-quinomethanes

Kim, Shokaku; Kitano, Yoshikazu; Tada, Mizuki; Chiba, Kazuhiro

doi:10.1016/s0040-4039(00)01216-8

Cited by 32 publications

(54 citation statements)

References 17 publications

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“…Subsequently, various bases were screened, and the results indicated that when KOH as the base could give desired product in the highest yield (93 %, Table 1, entry 4), whereas other common bases such as K 2 CO 3 , NaHCO 3 , KOAc, Et 3 N, DABCO proved less efficient for this transformation (Table 1, entries 4-11). Further, to improve the yield of product, the solvents like DMF, xylene, toluene and dioxane were also surveyed using KOH as base, and no better yields were obtained than DMSO as a solvent for the generation of 2 a (93 %, entry 4 and entries [12][13][14][15]. Finally, to render to further enhance the yield of the transformation, a change in the amount of elemental sulfur was also investigated.…”

Section: Resultsmentioning

confidence: 99%

“…62, 150.49, 149.19, 147.60, 142.91, 135.43, 133.61, 131.41, 130.66, 127.99, 127.06, 35.51, 35.05, 34.13, 29.65, 29.59, 23.86. 13 C NMR (101 MHz, CDCl 3 ) δ 186. 42, 150.32, 149.03, 147.28, 142.88, 135.41, 130.65, 128.91, 127.87, 124.50, 113.01, 111.31, 56.03, 55.91, 35.51, 35.01, 29.66, 29.56.…”

Section: 6-di-tert-butyl-4-(4-isopropylbenzylidene)cyclohexa-25-dien-...mentioning

confidence: 99%

“…1 H NMR (400 MHz, CDCl 3 ) δ 7.60 (s, 1H), 7.11 (s, 1H), 6.99 (s, 1H), 6.70 (s, 2H), 3.90 (d, J = 10.0 Hz, 9H), 1.31 (d, J = 5.1 Hz, 18H). 13 C NMR (101 MHz, CDCl 3 ) δ 186. 48, 153.37, 149.31, 147.72, 142.57, 139.23, 135.20, 131.56, 131.39, 127.81, 107.73, 61.10, 56.20, 35.56, 35.06, 29.68, 29.55.…”

Section: 6-di-tert-butyl-4-(345-trimethoxybenzylidene)cyclohexa-25-di...mentioning

confidence: 99%

“…1 H NMR (400 MHz, CDCl 3 ) δ 7.82 (d, J = 7.3 Hz, 2H), 7.77 (s, 2H), 7.59 (t, J = 7.4 Hz, 1H), 7.51 (t, J = 7.4 Hz, 2H), 5.80 (s, 1H), 1.49 (s, 18H). 13 C NMR (101 MHz, CDCl 3 ) δ 196. 38, 158.21, 138.67, 135.69, 131.74, 129.83, 128.92, 128.26, 128.13, 34.46, 30.24…”

Section: -(4-bromobenzylidene)-26-diisopropylcyclohexa-25-dien-1-onementioning

confidence: 99%

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Elemental Sulfur‐Promoted Synthesis of 4‐Hydroxybenzophenones from p‐Quinone Methides under Metal‐Free Condition

Wang

et al. 2022

Eur J Org Chem

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Conventional methods for the general and efficient synthesis of 4‐hydroxybenzo‐ phenones are extremely underdeveloped and limited. We herein report a challenging metal‐free protocol to rapidly construct 4‐hydroxybenzophenones from para‐quinone methides (p‐QMs) in DMSO in the presence of KOH using the inexpensive and readily available elemental sulfur as redox reagent. As an unprecedented method, this simple but efficient approach has excellent site specificity, green sustainability, excellent atomic economy, and broad functional group compatibilities. Mechanistic studies show that the novel reaction proceeds through a radical pathway.

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Section: Resultsmentioning

confidence: 99%

Section: 6-di-tert-butyl-4-(4-isopropylbenzylidene)cyclohexa-25-dien-...mentioning

confidence: 99%

Section: 6-di-tert-butyl-4-(345-trimethoxybenzylidene)cyclohexa-25-di...mentioning

confidence: 99%

Section: -(4-bromobenzylidene)-26-diisopropylcyclohexa-25-dien-1-onementioning

confidence: 99%

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Elemental Sulfur‐Promoted Synthesis of 4‐Hydroxybenzophenones from p‐Quinone Methides under Metal‐Free Condition

Wang

et al. 2022

Eur J Org Chem

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“…65 Osobito zanimljiv primjer upotrebe p-QM-a je u sintezi spirociklopropana koju je opisao Fan sa svojim suradnicima (shema 16).…”

Section: Sinteza Ciklopropilindolaunclassified

Kinon-metidi (I. dio): Reaktivni međuprodukti u kemiji fenola i njihova primjena u organskoj sintezi

2017

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Ovo djelo je dano na korištenje pod Creative Commons Attribution 4.0International LicenseInstitut Ruđer Bošković, Bijenička cesta 54, 10 000 Zagreb Sažetak Kinon-metidi (QM, naziv po IUPAC-u: kinometani) su reaktivni međuprodukti koji zauzimaju vrlo značajno mjesto u organskoj kemiji. Njihova primjena u organskoj sintezi je veoma velika, što je dovelo do razvoja velikog broja metoda za njihovo generiranje. Korisni su i u stereoselektivnim reakcijama, čime im je otvoren put za primjenu u totalnoj sintezi, nerijetko struktura koje su već pokazale značajnu biološku aktivnost. Ovim pregledom dan je uvid u metode sintetskog (termičkog) generiranja QM-a te njihovu primjenu u organskoj sintezi, s osvrtom na biološka svojstva samih QM-a ili produkata koji se iz njih dobivaju u sintezi. Ključne riječi Kinon-metidi, derivati fenola, termičko generiranje kinon-metida, kinon-metidi u organskoj sintezi, antiproliferativna aktivnost* Autor za dopisivanje: dr. sc. Đani Škalamera e-pošta: Djani.Skalamera@irb.hr ** Iako IUPAC više ne preporučuje upotrebu naziva kinon-metid, već preporučuje kinometan, autori ovog pregleda odlučili su zadržati stari naziv kinon-metid. Razlog tome je ponajprije usklađenost ovog članka sa svom ostalom relevantnom i recentnom literaturom o kinon-metidima, koja se koristi upravo tim nazivom. 354Đ. ŠKALAMERA et al.: Kinon-metidi (I. dio): Reaktivni međuprodukti u kemiji fenola…, (2017) 353−372 Osim osnovnih (roditeljskih) QM-a 1-3, u literaturi je uobičajeno kinon-metidima nazivati i sve ostale spojeve koji u svojoj strukturi sadrže metilensku i karbonilnu skupinu u vinilognom položaju. Tako se kinon-metidima nazivaju i derivati srodni m-QM-u 2, uobičajeni kod spojeva kod kojih zbog nemogućnosti konjugacije između metilenske skupine i kisika odgovarajući QM ima zwitterionski ili biradikalski karakter. Primjeri za navedene slučajeve prikazani su slikom 3.Slika 3 -Primjer neutralnog 6 2a i zwitterionskog 7 21 QM-a Fig. 3 -Example of neutral 6 2a and zwitterionic 7 21 QM Svojstva i kemijska reaktivnost kinon-metidaQM su reaktivne kratkoživuće vrste, vremena života tipično od <1 ns pa do nekoliko minuta, te je stoga za njihovo proučavanje potrebno primjenjivati tehnike tranzijentne spektroskopije, primjerice lasersku pulsnu fotolizu (LFP, od engl. laser flash photolysis). QM reagiraju s elektrofilima preko kisikova atoma, na način koji je tipičan za fenolate, a s nukleofilima reagiraju na metilenskom položaju pri čemu nastaju produkti Michaelove adicije 10 (shema 1). Kako su QM znatno reaktivniji od običnih enona kakvi su npr. α,β-nezasi eni ketoni, oni mogu reagirati i u [4+2] cikloadicijskim reakcijama (Diels-Alder) s dienofilima bogatim elektronima daju i kao produkte derivate kromana 9 (shema 1).Rearomatizacija koja se događa u reakciji adicije ujedno je i pokretačka sila navedenih reakcija. Supstituenti na QM znatno utječu na brzinu reakcija, te tako mogu utjecati na duljinu vremena života QM-a. 22 Obično su QM sami po sebi elektronski siromašni, pa će zbog toga elektron-odvlačeće skupine djelo...

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Preparation of Alkyls, Methylenes, and Aryls

Smith

2009

Compendium of Organic Synthetic Methods

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Alkylindan synthesis via an intermolecular [3+2] cycloaddition between unactivated alkenes and in situ generated p-quinomethanes

Cited by 32 publications

References 17 publications

Elemental Sulfur‐Promoted Synthesis of 4‐Hydroxybenzophenones from p‐Quinone Methides under Metal‐Free Condition

Elemental Sulfur‐Promoted Synthesis of 4‐Hydroxybenzophenones from p‐Quinone Methides under Metal‐Free Condition

Kinon-metidi (I. dio): Reaktivni međuprodukti u kemiji fenola i njihova primjena u organskoj sintezi

Preparation of Alkyls, Methylenes, and Aryls

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