Synthesis and resolution of 1,1-bi-8-methylisoquinoline: Formation of an optically active complex with high chiral recognition

Chelucci, Giorgio; Cabras, M. A.; Saba, Antonio; Sechi, Alessandra

doi:10.1016/0957-4166(96)00107-3

Cited by 31 publications

(12 citation statements)

References 14 publications

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“…This result is important for further practical use of this new chiral matrix, because the conformational rigidity of palladacycles enhances their ability for chiral recognition. [36,52,53,63,70,71] NϪH protons of the primary amino group is difficult to predict. Taking into account the similar dihedral angles H ax ϪNϪPdϪP and H eq ϪNϪPdϪP, found for adduct 4a The most important dihedral angles between the C α ϪH and the pseudo-axial and pseudo-equatorial NϪH bonds for in the crystal (110.7°and Ϫ130.9°, respectively), it is conceivable to suggest that both NH protons may reveal a spin-the λ(S) conformation are equal to ca.…”

Section: Structure Of Complexes 1a؊4a In Solutionmentioning

confidence: 99%

Steric Promotion of Aromatic C–H Bond Activation in Primary Benzylamines

Dunina¹,

Кузьмина

Kazakova

et al. 1999

Eur. J. Inorg. Chem.

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ortho‐Palladation of a sterically crowded primary benzylamine, α‐phenylneopentylamine, was accomplished in a moderate yield of 50% in the reaction with the weakest of palladation agents (Li2PdCl4) under very mild conditions, due to a steric promotion of an aromatic C–H bond activation. The structure of dimer 1a thus formed and the palladacycle conformation were established on the basis of 1H‐NMR spectroscopy of its mononuclear derivatives with [D5]pyridine (3a) and triphenylphosphane (4a), and an X‐ray investi‐gation of the latter.

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Section: Structure Of Complexes 1a؊4a In Solutionmentioning

confidence: 99%

Steric Promotion of Aromatic C–H Bond Activation in Primary Benzylamines

Dunina¹,

Кузьмина

Kazakova

et al. 1999

Eur. J. Inorg. Chem.

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“…Attempts to resolve the parent compound 3 via the tartrate salt of the protonated ligand were unsuccessful, with mutorotation occurring in aqueous solution within 80 s in 0.3 M hydrochloric acid [ 41 ]. Chiral stationary phases [ 42 ] and complexation with chiral palladium complexes [ 43 , 44 ] have been used for the resolution of 3 and 8,8′-dialkyl derivatives [ 45 , 46 ]. Steric interactions are increased with the presence of substituents on the nitrogen atoms, and, in contrast to 3 itself, 1,1′-biisoquinoline N,N’ -dioxide [ 47 , 48 ] and 8,8′-(MeO) 2 biiq N,N’ -dioxide [ 42 ] can also be resolved on chiral solid phases.…”

Section: Atropisomerismmentioning

confidence: 99%

“…Steric interactions are increased with the presence of substituents on the nitrogen atoms, and, in contrast to 3 itself, 1,1′-biisoquinoline N,N’ -dioxide [ 47 , 48 ] and 8,8′-(MeO) 2 biiq N,N’ -dioxide [ 42 ] can also be resolved on chiral solid phases. Somewhat unexpectedly, the rate of racemization increases in the sequence 8,8′-Me 2 biiq < 8,8′-Et 2 biiq < 8,8′- i Pr 2 biiq, with activation energies at 303 K being close to 100 kJ mol –1 [ 43 , 46 ]. Various chiroptical correlations have been used to show that the (+)-forms of 1,1′-biisoquinolines possess the (1 M ) absolute configuration ( Figure 4 ) [ 42 , 45 , 46 , 49 , 50 , 51 ].…”

Section: Atropisomerismmentioning

confidence: 99%

“…The reaction of 1-bromoisoquinoline with either sodium or magnesium does not yield 3 [ 79 ]. The coupling of 1-haloisoquinolines has been achieved with Zn–[NiBr 2 (PPh 3 ) 2 ] [ 47 , 82 ], Zn–[NiBr 2 (PPh 3 ) 2 ]–(Et 4 N)I [ 70 , 83 ], Zn–NiCl 2 –PPh 3 [ 43 , 44 , 45 , 46 , 84 , 85 , 86 , 87 ] or In–[Pd(PPh 3 ) 4 ] [ 88 ] catalysts. Substituted derivatives of biiq which have been prepared using this approach include 3,3′-Me 2 biiq [ 84 ], 8,8′-Me 2 biiq [ 45 , 46 ], 3,3′-Et 2 biiq [ 84 ], 8,8′-Et 2 biiq [ 45 , 46 ], 3,3′-( i Pr) 2 biiq [ 84 ], 8,8′-( i Pr) 2 biiq [ 45 , 46 ], 8,8′-( t Bu) 2 biiq [ 45 , 46 ], 3,3′-Ph 2 biiq [ 84 ], 3,3′-(2-py) 2 biiq [ 84 ], 6,6′-(MeO) 2 biiq [ 84 ], 3,3′-(MeO 2 C) 2 biiq [ 83 ], 3,3′-(HO 2 C) 2 biiq [ 83 ], 4,4′-(C n H 2 n +1 O) 2 biiq ( n = 1–11, 13, 17) [ 86 ], 4,4′-{ n ROC 6 H 4 O(CH 2 ) n O} 2 biiq ( R = C 6 H 13 , C 8 H 17 ; n = 4, 6) [ 86 ].…”

Section: Synthesis Of 11′-biisoquinolinesmentioning

confidence: 99%

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1,1′-Biisoquinolines—Neglected Ligands in the Heterocyclic Diimine Family That Provoke Stereochemical Reflections

2021

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1,1′-Biisoquinolines are a class of bidentate nitrogen donor ligands in the heterocyclic diimine family. This review briefly discusses their properties and the key synthetic pathways available and then concentrates upon their coordination behaviour. The ligands are of interest as they exhibit the phenomenon of atropisomerism (hindered rotation about the C1–C1′ bond). A notation for depicting the stereochemistry in coordination compounds containing multiple stereogenic centers is developed. The consequences of the chirality within the ligand on the coordination behaviour is discussed in detail.

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“…Fixing of the latter permits complex formation with Ru(II) or Os(II) [16,17]. Introduction of a substituent into position 8 increases the energetic barrier to rotation and hence for 8,8'-dialkyl-1,1'-bisisoquinolines also makes possible the formation of atropoisomers [18][19][20].…”

mentioning

confidence: 99%

Symmetrical and Unsymmetrical Bis-1,1′-(3,4-dihydroisoquinolines)

Глушков

Karmanov

Shklyaev

2005

Chem Heterocycl Compd

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Shklyaev3,3,-Dialkyl-1-cyano-3,4-dihydroisoquinolines were prepared by Beckmann defragmentation of ethyl α-(3,3-dialkyl-3,4-dihydroisoquinol-1-yl)-α-hydroximinoacetates and they take part in a Ritter reaction to form substituted bis-1,1'-(3,4-dihydroisoquinolines).As heterocyclic analogs of 1,1'-binaphthyl systems, bis-1,1'-isoquinolines are promising ligands for the preparation of metallocomplex catalysts since coordination with a metal is possible at the nitrogen atoms [1]. A method is known for the Ullman preparation [2] of bis-1,1'-isoquinolines while 3,4-dihydro derivatives are not formed under these conditions and they are rather inaccessible compounds. Bis-1,1'-(3,4-dihydroisoquinolines) unsubstituted in position 3 have been previously obtained using a Bischler-Napieralski reaction by the action of POCl 3 in acetonitrile [3] or Tf 2 O in the presence of 4-N,N-dimethylaminopyridine [4] on the corresponding oxamide. In the current work we propose a route to bis-1,1'-(3,4-dihydroisoquinolines) which is based on the Ritter reaction [5,6].A second order Beckmann rearrangement [7,8] of ethyl α-(3,3-dialkyl-3,4-dihydroisoquinol-1-yl)-αhydroximinoacetates 1a-c using the method [9, 10] gave the nitriles 2a-c. Despite the simplicity it should be noted that the indicated method is poorly reproducible in our hands, the yields of the products 2 differing markedly from one experiment to another.The nitrile 2a was also prepared by the dehydration of 3,3-dimethyl-3,4-dihydroisoquinolylaldoxime 3 [11] in refluxing xylene using a known method [12] (see Experimental section. The hydrochloride 3.HCl has been reported before [13]).The Ritter reaction of nitriles 2a-c and carbinols 4a-c (stirring the reagents in a mixture of toluene and conc. H 2 SO 4 at 20°C) gave 42-71% yields of compounds 5a-e (Tables 1 and 2). According to this scheme another combination of nitrile and carbinol is possible which leads to both symmetrical and unsymmetrical bis-1,1'-(3,4-dihydroisoquinolines) 5. Compound 5c was also prepared in somewhat lower yield (37%) by the condensation of nitrile 2b with veratrole and isobutylene oxide using method [14] (Scheme 1).A feature of the 1 H NMR spectrum of compound 5b is the small shift of the H-8 signal of the 6,7-dimethoxy-substituted ring to high field by about 0.2 ppm when compared with the H-8 signal of 6,7-dimethoxy-1,3,3-trimethyl-3,4-dihydroisoquinoline [14] and this is due to the anistropic effect of the neighboring 3,4-dihydroisoquinoline fragment. A similar high field shift caused by a benzene ring has previously been observed by us in the case of 6,7-dimethoxy-3,3-dimethyl-1-phenyl-3,4-dihydroisoquinoline [14].0009-3122/05/4104-0475©2005 Springer Science+Business Media, Inc. nitrile 2b (0.3 g, 1.23 mmol) and carbinol 4a (0.2 ml, 1.25 mmol) in toluene (20 ml) was added to conc. H 2 SO 4 (10 ml) and the mixture obtained was stirred for 2 h at 20°C and poured into water (100 ml).The aqueous layer was separated, washed with toluene (15 ml) and NH 4 OH (25%) was then added to pH ~ 8. The product was ext...

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Synthesis and resolution of 1,1-bi-8-methylisoquinoline: Formation of an optically active complex with high chiral recognition

Cited by 31 publications

References 14 publications

Steric Promotion of Aromatic C–H Bond Activation in Primary Benzylamines

Steric Promotion of Aromatic C–H Bond Activation in Primary Benzylamines

1,1′-Biisoquinolines—Neglected Ligands in the Heterocyclic Diimine Family That Provoke Stereochemical Reflections

Symmetrical and Unsymmetrical Bis-1,1′-(3,4-dihydroisoquinolines)

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