A new approach for the determination of the absolute configuration of secondary alcohols by 1H NMR with O-substituted mandelate derivatives

Chataigner, Isabelle; Lebreton, Jacques; Durand, Didier; Guingant, André; Villiéras, J.

doi:10.1016/s0040-4039(98)00059-8

Cited by 42 publications

(32 citation statements)

References 21 publications

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“…The shielding by MaNP and 9-AMA can be so substantial that only the (R)-or (S)-derivative is needed with some substrates to make a reliable assignment. Other reagents, such as (R)- (2) and (S)-(1)-a-methoxyphenylacetic acid (MPA; 4), 2,[8][9][10] (R)- (1) and (S)-(2)-a-cyano-afluoro-p-tolylacetic acid (CFTA; 5), 11,12 and (R)- (2) and (S)-(1)-mandelic acid (6), 2,13 have a greater preference than MTPA derivatives for the preferred conformation that results in larger shielding from the phenyl ring. The use of aryl-containing carboxylic acids for assigning absolute configuration by NMR has been the focus of a comprehensive review.…”

Section: Oxygen-containing Compounds Secondary Alcoholsmentioning

confidence: 99%

“…The Pr(III) binds to the oxygen of the hydroxyl group through a donoracceptor interaction. The broadening from the paramagnetic Pr(III) is at acceptable levels in the 13 C NMR spectrum. 25 Database method.…”

mentioning

confidence: 96%

“…The method is suitable for assigning the configuration of acyclic, cyclic, biaryl, and benzyl alcohols. 24 Similarly, the 13 C resonances of carbon atoms adjacent to the secondary hydroxyl group in the presence of Pr(hfc) 3 (hfc 5 3-(heptafluorobutyryl)-d-camphorate) have Dd RS values that correlate with absolute configuration. The Pr(III) binds to the oxygen of the hydroxyl group through a donoracceptor interaction.…”

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confidence: 99%

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Assignment of absolute configuration using chiral reagents and NMR spectroscopy

2010

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Section: Oxygen-containing Compounds Secondary Alcoholsmentioning

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Assignment of absolute configuration using chiral reagents and NMR spectroscopy

2010

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“…After removal of the mandeloyl group from each ester, diastereomerically pure 6a and 6b were obtained. The newly introduced stereocenter of C-1 in 6b was determined as depicted using the D d values of the (S)-and (R)-mandelic esters derived from 6b in their 1 H-NMR spectra [7]. The stereochemically defined allylic alcohol 6a was subjected to the Sharpless VO(acac) 2 -catalyzed epoxidation [8], affording epoxy alcohols 7 as a 2 : 1 diastereomeric mixture.…”

Section: Introductionmentioning

confidence: 99%

“…After protection of the hydroxyl groups, syn-and anti-epoxy MOM ethers 9a and 9b were cleanly separated. The stereochemistry at C-2 of 9b was unambiguously established based on the 1 H NMR difference (D d ) of the corresponding (S)-and (R)-O-acetylmandeloyl esters prepared from 9b by regioselective hydride opening of the epoxy ring followed by esterification [7]. The opening of the epoxy ring of 9a with a two-carbon nucleophile was investigated.…”

Section: Introductionmentioning

confidence: 99%

Total Syntheses of (+)-1893B and Its Three Diastereomers and Evaluation of Their Biological Activities

et al. 2006

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The total syntheses of natural (ϩ)-1893B (2) and three other diastereomers 14, 18, and 21 were accomplished. Starting from the sequential metathesis product 5 prepared in turn from a 7-oxanorbornene derivative (ϩ)-4, 2 was synthesized by means of an epoxyring opening of 9a with trimethylsilylacetylide followed by Wacker-type oxidation of the resulting alkyne 10 for the construction of the g-lactone moiety. By applying the same synthetic sequence, three additional diastereomers of 2, 14, 18, and 21 were also synthesized. The biological activities of previously synthesized 1893A (1), 1893B (2), and the diastereomers of 1893B 14, 18, and 21 were investigated. Introduction1893A (1) and 1893B (2) were isolated in 2003 during the course of antitumor natural products searching from a marine endophytic fungus designated as No. 1893, which exists in mangroves (Fig. 1) [1]. Lin and Chen reported that the extract mixture of No. 1893 appeared to exhibit cytotoxic and insecticidal activities. However, the biological activity of the pure metabolites 1 and 2 has not reported. The structure of 1 was elucidated by extensive spectroscopic studies and finally determined by X-ray crystallographic analysis. As structurally related natural product, (ϩ)-mycoepoxydiene (3) was isolated in 1999 [2,3]. We already reported the total syntheses of 1 and 3, which were characterized by a sequential ringopening/cross/ring-closing metathesis strategy [4,5]. Although the stereostructures of 1 and 3 were confirmed by our synthetic studies, the stereochemistry of 2 was not unambiguously established at that time. Later, we were concerned with the stereochemically defined total synthesis of 2 through the total syntheses of all four possible stereoisomers regarding the vicinal diol moiety in 2. The first total synthesis of natural (ϩ)-2 was reported as a preliminary communication [6]. Herein, we describe in detail the total syntheses of 2 and three additional diastereomers. The evaluation of their biological activities is also presented. Results and DiscussionAccording to our previous report [5], we converted the enantioenriched 7-oxanorbornene derivative (ϩ)-4 (Ͼ95% ee) into the cyclooctadiene 5 through a one-pot ring-expansion metathesis strategy (Scheme 1). The

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2018

Differentiation of Chiral Compounds Using NMR Spectroscopy

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A new approach for the determination of the absolute configuration of secondary alcohols by 1H NMR with O-substituted mandelate derivatives

Cited by 42 publications

References 21 publications

Assignment of absolute configuration using chiral reagents and NMR spectroscopy

Assignment of absolute configuration using chiral reagents and NMR spectroscopy

Total Syntheses of (+)-1893B and Its Three Diastereomers and Evaluation of Their Biological Activities

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