Tartaric acid derivatives chiral hosts

Chirality has also been introduced into crown hosts using optically-active functional groups other than bis-/ -naphthol. For example, the crown (233) derived from L-tartaric acid is a chiral host showing much less... 

Among the different types of compounds whose complexation properties have been studied are various amides linear oxoamide 9 [22], fumaramide 10 [23,24] and methanetricarboxamide 11 [25], biphenyl derivatives 12 [26], and derivatives of tartaric acid 13-16, that can also be prepared in an optically active form [27], The above-mentioned chiral hosts have been found to form inclusion complexes with chiral guests 17 and 18. Molecular recognition between chiral hosts and... 

Some amide derivatives have been reported to form inclusion complex with a wide variety of organic compounds.9 Optically active amide derivatives are expected to include one enantiomer of a racemic guest selectively. According to this idea, some amide derivatives of tartaric acid (11-13) were designed as chiral hosts.10 As will be described in the following section, these amide hosts were found to be useful for resolution of binaphthol (BNO) (14) and related compounds (15,16). 

Optical resolution of some hydrocarbonds and halogeno compounds by inclusion complexation with the chiral host (9a) has been accomplished.11,12 Preparation of optically active hydrocarbons is not easy and only a few example of the preparation of optically active hydrocarbons have been reported. For example, optically active 3-phenylcyclohexene has been derived from tartaric acid through eight synthetic steps.11 Although one-step synthesis of optically active 3-methylcyclohexene from 2-cyclo- hexanol by the Grignard reaction using chiral nickel complex as a catalyst has been reported, the enantiomeric purity of the product is low, 15.9%.11 In this section, much more fruitful results by our inclusion method are shown. 

Toda, F., Tanaka, K., and Okuda, T. (1995) Optical Resolution of Methyl Phenyl and Benzyl Methyl Sulfoxides and Alkyl Phenylsulfinates by Complexation with Chiral Host Compounds Derived from Tartaric Acid, J. Chem. Soc., Chem. Commun., 639-640. 

Toda, F., and Tanaka, K. Efficient optical resolution of 2,2 -dihydroxy-binaphtyl and related compounds by complex formation with novel chiral host compounds derived from tartaric acid, J. Org. Chem. 1988, 53, 3607-3609. 

Tanaka, K., Honke, S., Urbanczyk-Lipkowska, Z., and Toda, F. New chiral hosts derived from dimeric tartaric acid efficient optical resolution of aliphatic alcohols by inclusion complexation, J. Org. Chem. 2000,(55,3171-3176. 

The enantioselective reduction of acylpyridines has been improved by the addition of trimethoxyborane to the oxazaborolidine reagent <97SL273, 97T12405>. An alkyl pyridyl sulfoxide is resolved by complexation with a chiral host compound derived from tartaric acid <97TA2505>. 

Preparation of enantiomerically active hydrocarbons is difficult and only a few examples of the preparation of chiral hydrocarbons have been reported. For example, chiral 3-phenylcyclohexene has been derived from tartaric acid through eight synthetic steps. Enantiomeric separation by host-guest complexation with a chiral host is more fruitful for the preparation of chiral hydrocarbons. For example, when a solution of fR,Rh( )-t ws-4,5-bis(hydroxydiphenylmethyl)-l,4-dioxaspiro[4.4]-nonane (lb) [2] (3 g, 6.1 mmol) and rac-3-methylcyclohexene (2a) (0.58 g, 6.1 mmol) in ether (15 ml) was kept at room temperature for 12 h, a 2 1 inclusion complex of lb and 2a (2.5 g, 75%) was obtained as colorless prisms in the yield indicated. The crystals were purified by recrystallization from ether to give the inclusion complex (2.4 g, 71%), which upon heating in vacuo gave (-)-2a of 75% ee by distillation (0.19 g, 71%) [3]. By the same inclusion complexation, (-i-)-4-methyl- (2b) (33% ee, 55%), (-)-4-vinylcyclohexene (2c) (28% ee, 73%), (-)-bicyclo[4.3]-nonane-2,5-diene... 

Carbohydrates or carbohydrate-derived compounds were used to promote asymmetric induction in the crystalline state. In particular, enantio-selective photocyclization of a-ketoamide 105 in the clathrate crystalline environment with chiral hosts 106 and 107 derived from tartaric acid provided the /9-lactam 108 with high enantiomeric purity (Scheme 28) [81]. 

Considerable work has been done in the field of chiral hosts capable of discriminating between enantiomeric guest molecules. A variety of chiral residues either synthetic or derived from natural products l (sugars, tartaric acid, amino acids etc.) have been fused to macrocyclic rings. In most cases, chiral primary ammonium cations have been the guest species of choice, although the complexation of chiral carboxylates has been examined to some extent 2]. 

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