ChemInform Abstract: PREPARATION OF AUXILIARIES FOR ASYMMETRIC SYNTHESES FROM TARTARIC ACID. ADDITION OF BUTYLLITHIUM TO ALDEHYDES IN CHIRAL MEDIA

Seebàch, Dieter; Kalinowski, H.‐O.; Bastani, Bahram; Crass, Gerhard; Daum, Hermann; Doerr, H.; Dupreez, Nicolaas P.; Ehrig, Volker; Langer, Werner; Nuessler, C.; Oei, Hoc-An; Schmidt, M.

doi:10.1002/chin.197731073

Cited by 5 publications

(8 citation statements)

References 1 publication

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“…These polymers were highly isotactic (mm 2 98%). These results are very contrast to the results of polymerization with the complexes of 20 (runs 25 and 26 in Table 4). PMP and 20 possess the same absolute configuration and PMP differs from 20 only in the substituent group bonded to the nitrogen atom; a proton for PMP and a methyl group for 20.…”

Section: Resultscontrasting

confidence: 85%

“…In the present paper, detailed results on the polymerization of D2PyMA with the complexes of 20), ( -)-(2S,2'S)-2-(2'-hydroxymethylpyrrolidin-1 '-yllmethyl-1-methylpyrrolidine (21 ), and ( + )-(S)-2-(1-pyrrolidinylmethyl)pyrrolidine (22,PMP).…”

Section: Introductionmentioning

confidence: 99%

“…In the present paper, detailed results on the polymerization of D2PyMA with the complexes of FlLi and DPEDA-Li with 22 chiral ligands are reported; the ligands are Sp, DDB, ( + )-(2S,3S)-2,3-dimethoxy-1,4-bis(diethylamino)butane (3), ( + )-(2S,3S)-2,3-dimethoxy-1,4-di(l-pyrrolidinyl)butane (41, ( + )-(2S,3S)-2,3-dimethoxy-l,4-dipiperidinobutane (51, (19), ( -)-(S)-l-methyl-2-(l-pyrrolidinyl-methy1)pyrrolidine (20), ( -)-(2S,2'S)-2-(2'-hydroxymethylpyrrolidin-1 '-yllmethyl-1-methylpyrrolidine (21 ), and ( + )-(S)-2-(1-pyrrolidinylmethyl)pyrrolidine (22,PMP).…”

Section: Introductionmentioning

confidence: 99%

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Helix‐sense‐selective polymerization of diphenyl‐2‐pyridylmethyl methacrylate with chiral anionic initiators

et al. 1991

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Polymerization of diphenyl-2-pyridylmethyl methacrylate was carried out with the complexes of organolithium compounds with 22 chiral ligands. Helix-sense-selectivity of the polymerization was largely affected by a slight structural difference of chiral ligands. ( + )-(S)-2-( 1-Pyrrolidinylmethy1)pyrrolidine was the most effective ligand in producing a one-handed helical polymer with narrow molecular weight distribution.

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Section: Resultscontrasting

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Helix‐sense‐selective polymerization of diphenyl‐2‐pyridylmethyl methacrylate with chiral anionic initiators

et al. 1991

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“…44 1,4-Di-O-methyl-2,3-O-isopropylidene-L-threitol (2a) (10.8 g, 56.7 mmol), methanol (50 ml, 15 ml, and 2 x 20 ml), 0.5 M aq. HCl (5 ml, then 3 ml).…”

Section: General Procedures For Preparation Of Di-o-alkyl-l-threitolsmentioning

confidence: 99%

Synthesis of l‐threitol‐based crown ethers and their application as enantioselective phase transfer catalyst in Michael additions

et al. 2017

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A few new l-threitol-based lariat ethers incorporating a monoaza-15-crown-5 unit were synthesized starting from diethyl l-tartrate. These macrocycles were used as phase transfer catalysts in asymmetric Michael addition reactions under mild conditions to afford the adducts in a few cases in good to excellent enantioselectivities. The addition of 2-nitropropane to trans-chalcone, and the reaction of diethyl acetamidomalonate with β-nitrostyrene resulted in the chiral Michael adducts in good enantioselectivities (90% and 95%, respectively). The substituents of chalcone had a significant impact on the yield and enantioselectivity in the reaction of diethyl acetoxymalonate. The highest enantiomeric excess (ee) values (99% ee) were measured in the case of 4-chloro- and 4-methoxychalcone. The phase transfer catalyzed cyclopropanation reaction of chalcone and benzylidene-malononitriles using diethyl bromomalonate as the nucleophile (MIRC reaction) was also developed. The corresponding chiral cyclopropane diesters were obtained in moderate to good (up to 99%) enantioselectivities in the presence of the threitol-based crown ethers.

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“…A similar methylation of the D enantiomer proceeded in 77% yield (19). Phase-transfer-catalyzed nucleophilic methylation with dimethyl sulfate (a variation on the Haworth method) proceeded in 67% yield (18). In other work in which 1 ,4-anhydro-L-threitol had been prepared, we had found that protection of diethyl tartrate with THP groups, needed for the cyclization of a 2,3-protected threitol, was convenient for small-scale work, proceeding quantitatively even without catalysis4.…”

Section: Syntheses Of Dmt and Tmmmentioning

confidence: 99%

The solution structures of chiral Ti⁴⁺ alkoxides

Potvin¹,

Gau²,

Kwong³

et al. 1989

Can. J. Chem.

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. 67,1523 (1989).1,4-Di-0-methyl-L-threitol and 1,2,5,6-tetra-0-methyl-L-mannitol were prepared by new, more convenient, and higher yielding routes. These and 1 ,2;5,6-di-0-isopropylidene-D-mannitol formed 2:2 complexes with Ti(OiPr),, but did not readily form 1:2 complexes in the presence of excess ~i~+ .'H and I3C nuclear magnetic resonance spectra showed that the structures in solution of the 2:2 complexes were analogous to solid-state structures of tartaric acid derivatives, i.e., possessing bridging diolate oxygens. In contrast, R,R-and meso-diisopropyl tartrates, N,N1-dibenzyl tartramide, and N,N1-di(2-pheny1)ethyl tartramide behaved very differently. The tartramides formed mixtures of complexes that became dominated by 2:3 complexes in the presence of excess T i ( 0 '~r )~. Two tertiary tartramides failed to provide well-defined complexes. The R,R-tartrate formed a monocyclic (nonbridged) 2:2 complex, but an equilibrating mixture of 1:2 and 2:2 complexes with excess ~i~+ .The equilibrium shifted upon cooling toward a 1:2 complex possessing a bridging diolate oxygen, as did the meso 1:2 complex. Other temperature-dependent phenomena were also studied.

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ChemInform Abstract: PREPARATION OF AUXILIARIES FOR ASYMMETRIC SYNTHESES FROM TARTARIC ACID. ADDITION OF BUTYLLITHIUM TO ALDEHYDES IN CHIRAL MEDIA

Abstract: Die Darstellung von etwa 70 chiralen Verbindungen unterschiedlichster Struktur vom Typ 1,2‐diheterosubstituiertes Äthan (Heteroatome O, N, S) ist beschrieben.

Cited by 5 publications

References 1 publication

Helix‐sense‐selective polymerization of diphenyl‐2‐pyridylmethyl methacrylate with chiral anionic initiators

Helix‐sense‐selective polymerization of diphenyl‐2‐pyridylmethyl methacrylate with chiral anionic initiators

Synthesis of l‐threitol‐based crown ethers and their application as enantioselective phase transfer catalyst in Michael additions

The solution structures of chiral Ti⁴⁺ alkoxides

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ChemInform Abstract: PREPARATION OF AUXILIARIES FOR ASYMMETRIC SYNTHESES FROM TARTARIC ACID. ADDITION OF BUTYLLITHIUM TO ALDEHYDES IN CHIRAL MEDIA

Abstract: Die Darstellung von etwa 70 chiralen Verbindungen unterschiedlichster Struktur vom Typ 1,2‐diheterosubstituiertes Äthan (Heteroatome O, N, S) ist beschrieben.

Cited by 5 publications

References 1 publication

Helix‐sense‐selective polymerization of diphenyl‐2‐pyridylmethyl methacrylate with chiral anionic initiators

Helix‐sense‐selective polymerization of diphenyl‐2‐pyridylmethyl methacrylate with chiral anionic initiators

Synthesis of l‐threitol‐based crown ethers and their application as enantioselective phase transfer catalyst in Michael additions

The solution structures of chiral Ti4+ alkoxides

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The solution structures of chiral Ti⁴⁺ alkoxides