Regioselective ring-opening of epoxides with ortho-lithioanisoles catalyzed by BF3·OEt2

Ertürk, Erkan; Tezeren, Mustafa A.; Atalar, Taner; Tilki, Tahir

doi:10.1016/j.tet.2012.05.116

Cited by 22 publications

(8 citation statements)

References 94 publications

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“…Anisole has served as the benchmark for virtually all of these studies. Numerous other reports of the utilization of ortho-lithioanisole ( o -LiA) in synthesis have also been published with modest to good product yields being reported in most cases . We attribute most of these modest yields to initial incomplete ortho-lithiation of anisole.…”

Section: Resultsmentioning

confidence: 99%

ortho-Lithiations Reassessed: the Advantages of Deficiency Catalysis in Hydrocarbon Media

et al. 2013

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Hydrocarbon media based metalation procedures involving “deficiency catalysis” are described for the ortho-lithiation of anisole (A), p-chloroanisole (p-ClA), o-, m-, p-methylanisoles (o-, m-, p-MA), the three dimethoxybenzenes (DMB’s), dimethylaniline (DMA), dimethybenzylamine (DMBA), m-methoxydimethylaniline (m-MeODMA), and tetramethyl-p-phenylenediamine (p-TMPDA). These procedures involve certain mechanistic considerations, which must be fine-tuned to maximize the extent of metalation (EoM). Our working hypothesis is that a controlled deoligomerization of the n-BuLi hexamer found in hydrocarbon media will afford a “sweet spot” of deoligomerization such that a maximally efficient metalation medium can be formed. In many cases, a substoichiometric ratio of equivalent TMEDA to n-BuLi is 0.1–0.2:1.0, but certain substrates suffer multiple sites of metalation under these conditions, so different promoted hydrocarbon media systems incorporating measured equivalents of an ether have been formulated. This paper represents the summary of our successful efforts to render ortho-lithiations safer, greener, and more atom-economical by use of hydrocarbon solvent media. EoM’s of 11 of the 12 substrates under these atom-economical conditions range from 87 to 97%.

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Section: Resultsmentioning

confidence: 99%

ortho-Lithiations Reassessed: the Advantages of Deficiency Catalysis in Hydrocarbon Media

et al. 2013

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“…The racemic synthesis of the cis ‐AAP 1 started with the ring‐opening of cyclohexene oxide ( 3 ) with ortho ‐lithioanisole ( 4 ) in the presence of BF 3 · OEt 2 , as described in our previous report (Scheme ) . The ring‐opened product rac ‐ 5 could be easily prepared in almost quantitative yield (99 %).…”

Section: Resultsmentioning

confidence: 98%

“…trans ‐2‐(2‐Methoxyphenyl)cyclohexanol ( rac ‐5): An oven‐dried 1 L round‐bottomed Schlenk flask, capped with a glass stopper and equipped with a magnetic stirring bar, was evacuated under heating with a blow‐drier for 15 min. After the flask was cooled down to ambient temperature, dry nitrogen was back‐filled and the glass stopper was replaced with a rubber septum, under a positive pressure of nitrogen.…”

Section: Methodsmentioning

confidence: 99%

Enantiopure cis‐ and trans‐2‐(2‐Aminocyclohexyl)phenols: Effective Preparation, Solid‐State Characterization, and Application in Asymmetric Organocatalysis

et al. 2018

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Effective synthesis of cis‐ and trans‐2‐(2‐methoxyphenyl)cyclohexylamine as well as their multigram‐scale optical resolution by diastereomeric salt formation with dibenzoyl tartaric acid have been described. Assignment of absolute configurations to the enantiomers has been made by X‐ray crystallography. Starting from the resolved precursor, diverse aminoalkylphenols (AAPs) having primary, secondary, and tertiary amine group as well as a quaternary ammonium phenol have been prepared as potential bifunctional organocatalysts based on the cyclohexane backbone. We furthermore report herein that AAPs carrying a primary amine and a phenolic hydroxyl group can catalyze the direct aldol reaction with high activity and setereoselectivity, and thus up to 97 % yield, 90:10 syn/anti diastereomeric ratio, and 80 % enantiomeric excess can be achieved.

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“…Preparation of HAROLs (5 and 6, Figure 3) was described in our previous work [19]. The protected form of (S)-2-(3,5-di-tert-butyl-2-hydroxyphenyl)-1-phenylethanol ( 5) could be obtained in a one-pot synthesis strategy through the ring-opening of (R)styrene oxide with the corresponding lithioanisole [18]. On the other hand, the HAROL 6 could be obtained through the palladium-catalyzed α-arylation of indan-1-one with the respective ortho-bromoanisole, enantioselective reduction of the formed ketone, and demethylation, in order [19].…”

Section: Methodsmentioning

confidence: 99%

“…We recently developed chiral 2-(2-hydroxyaryl)alcohols (HAROLs) and 2-(2aminoalkyl)phenols (AAPs) as organocatalysts for the enantioselective Morita-Baylis-Hillman reaction and aldol reaction, respectively ( Figure 2) [18][19][20]. AAPs were also found to accelerate enantioselective diethylzinc addition reaction to benzaldehyde in high yields and enantioselectivities [21].…”

Section: Introductionmentioning

confidence: 99%

Asimetrik Hetero Diels-Alder Reaksiyonu için Organaokatalizör Olarak Kiral 1,4-Hidroksiarilalkoller (HAROL) ve 1,4-Aminoalkilfenoller (AAP)

Ertürk

Tezeren²,

Tilki³

2019

Süleyman Demirel Üniversitesi Fen Edebiyat Fakültesi Fen Dergisi

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In this study, two chiral 2-(2-hydroxyaryl) alcohols (HAROLs; 1,4-diols) and a 1,4aminoalkylphenol (AAP) were examined as hydrogen-bond donor (HBD) organocatalysts in the asymmetric hetero Diels-Alder (HDA) reaction of aldehydes with Rawal's diene. Catalytic amount (10 mol%) of the both scaffolds (HAROL and AAP) have been found to effect the HDA reaction in a quite efficient manner. Among them, a HAROL molecule based on indan backbone was turned out to be the best in terms of catalytic activity and enantioselectivity. On the other hand, AAP tested seemed to act as a bifunctional organocatalyst, i.e. as both a Lewis base and HBD organocatalyst. Experimental results underpins that a careful tuning of HAROL structure might lead to the development of more general HBD organocatalysts.

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Regioselective ring-opening of epoxides with ortho-lithioanisoles catalyzed by BF3·OEt2

Cited by 22 publications

References 94 publications

ortho-Lithiations Reassessed: the Advantages of Deficiency Catalysis in Hydrocarbon Media

ortho-Lithiations Reassessed: the Advantages of Deficiency Catalysis in Hydrocarbon Media

Enantiopure cis‐ and trans‐2‐(2‐Aminocyclohexyl)phenols: Effective Preparation, Solid‐State Characterization, and Application in Asymmetric Organocatalysis

Asimetrik Hetero Diels-Alder Reaksiyonu için Organaokatalizör Olarak Kiral 1,4-Hidroksiarilalkoller (HAROL) ve 1,4-Aminoalkilfenoller (AAP)

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