The titanium tetrachloride induced synthesis of N-phosphinoylimines and N-sulphonylimines directly from aromatic aldehydes

Jennings, W. Brian; Lovely, Carl J.

doi:10.1016/s0040-4020(01)80987-x

Cited by 171 publications

(85 citation statements)

References 15 publications

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“…Additives are also commonly used for these reactions. Therefore, in order to see the effect of additives on our catalyst system i Pr 2 NEt, Et 3 N, HMPA, DABCO, MeOH, and TMEDA were tried (entries [15][16][17][18][19][20]. After observing that TMEDA increased the enantioselectivity, it was decided to do further optimization by changing the amount and also the type of copper salt.…”

Section: Resultsmentioning

confidence: 99%

PFAM catalyzed enantioselective diethylzinc addition to imines

Doğan¹,

Çağli²

2015

Turk J Chem

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Chiral amines are important starting materials for the synthesis of biologically important compounds.Enantioselective addition of dialkylzinc reagents to imines is a reliable method for the synthesis of these compounds.Different chiral catalysts were developed and used for this method. Phosphorous based PFAM catalysts were tried for the first time in the enantioselective synthesis of amines by reacting diethylzinc with N-sulfonyl imines and Ndiphenylphosphinoyl imines. Chiral amines were isolated with moderate to acceptable yields and enantioselectivities.

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Section: Resultsmentioning

confidence: 99%

PFAM catalyzed enantioselective diethylzinc addition to imines

Doğan¹,

Çağli²

2015

Turk J Chem

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“…To overcome this problem, the addition reactions were carried out in the presence of activated, powdered MS 4A. As a result, the addition reaction of phenylboronic acid using a catalytic amount of the Rh-NHC complex was successfully applied to the arylation of N-phosphinoylarylimines 4a-d 39) that were derived from benzaldehyde, 4-chlorobenzaldehyde, 4-methylbenzaldehyde, and 2-naphthaldehyde, affording the corresponding addition products 5a-d in high yields (Table 4, entries 1-4). In the study by Charette et al, 4c was used as a substrate and the addition product 5c was obtained in 77% yield after heating for 36 h at 50°C.…”

Section: Resultsmentioning

confidence: 99%

Rh-N-Heterocyclic Carbene (NHC) Complex-Catalyzed Addition of Phenylboronic Acid to N-Sulfonyl and N-Phosphinoyl Aldimines

Bakar

Suzuki

Sato

2008

CHEMICAL & PHARMACEUTICAL BULLETIN

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973The synthesis, isolation, and characterization of stable Nheterocyclic carbenes (NHCs) first reported by Arduengo et al. 1) in 1991, have attracted attention for the use of NHCs as ancillary ligands for transition metal complexes. Due to their strong s-donating properties, NHCs can form metal complexes that have high stabilities toward heat, moisture, and air, and they have higher catalytic abilities than their phosphine counterparts. [2][3][4][5][6] NHCs are now used as ligands for transition metals in many important chemical transformations such as Pd-catalyzed coupling reactions, 7) Ru-catalyzed olefin metathesis, 8) Rh-catalyzed hydrosilylations, [9][10][11] and Cu-catalyzed conjugate addition reactions. [12][13][14] Moreover, NHCs have attracted considerable attention as organocatalysts in several reactions such as benzoin condensation, [15][16][17][18][19][20] Stetter reaction, [21][22][23] transesterification/acylation reactions, 24,25) and nucleophilic substitution reactions. [26][27][28] In our study on the use of NHCs as ligands in organic transformations, we have recently reported the addition of diethylzinc to N-sulfonylarylimines catalyzed by 29) where NHCs exhibit a strong ligand acceleration effect (LAE). This finding has prompted us to investigate the applicability of a similar methodology to the Rh-NHC complex-catalyzed addition of phenylboronic acid to imines.The addition reaction of organometallic reagents to imines is one of the most efficient procedures for the synthesis of diarylmethylamines, which are important subunits of biologically significant compounds. [30][31][32][33] Despite many studies on the Rh-phosphine complex-catalyzed addition of arylboronic acids to imines, 34,35) there is only one study, i.e., that by Charette and coworkers, in which the Rh-NHC complex is used.36) Here, we report our results on the addition of arylboronic acid to both N-sulfonylarylimines and N-phosphinoylarylimines by using a catalytic amount of Rh-NHC complexes. Results and DiscussionIn the study by Charette and coworkers, the Rh-NHC complex was prepared in situ using the NHC-transfer reagent Ag-NHC and used as a catalyst in the arylation of pmethylphenyl-N-phosphinoylimine with phenylboronic acid. 36) They showed only one reaction example. We examined the catalytic ability of the Rh-NHC complex generated in situ 37) from azolium salts and [RhCl(cod)] 2 for the arylation of imines. The Rh-NHC complex was prepared from [RhCl(cod)] 2 , 1,3-diadamantylimidazolium chloride 2a, and t-BuOK; then, N-sulfonylphenylimine 1a 38) and phenylboronic acid were added to the mixture. The reaction in dioxane at 70°C for 5 h afforded N-sulfonyldiarylmethylamine 3a in 91% yield (Table 1, entry 1). The reaction without 2a in dioxane afforded the desired product 3a in only 62% yield after 10 h at 70°C (entry 2). These results showed and indicated that the NHC ligand accelerated the addition reaction. The reaction in THF afforded 3a in 48% yield, whereas in toluene, the reaction was very sluggish and gave no adducts (Ta...

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“…This chemistry was applied unsuccessfully toward the synthesis of enolizable N-sulfonyl aldimines and unfortunately this method shares a common limitation with several other methods of N-tosylaldimine synthesis 18,33,34,36,37 in that it does not appear to be applicable to the synthesis of N-sulfonyl aldimines derived from aldol condensations being obtained instead. We have also studied the reaction of sulfonamide with ketones.…”

Section: Resultsmentioning

confidence: 99%

“…16 Several methods for the preparation of N-sulfonylimines have appeared in the literature. Lichtenburger and Kretar first prepared such compounds by a Lewis acid catalyzed direct condensation 17 , Jennings and Lovely used titanium tetrachloride and triethylamine for the synthesis of N-tosylimines 18 , rearrangements of sulfinate esters of oximes have also served as a convenient approach, Kresze pioneered an imine-transfer reaction with aromatic aldehydes utilizing sulfinylsulfonamides. 19,20 N,N'-Bis(ary1-sulfonylthio)-and selenodiimides 21 have also been effective but suffer from lack of chemoselectivity since they undergo Diels-Alder and ene reactions.…”

Section: Introductionmentioning

confidence: 99%