(<i>S</i>)‐(−)‐1‐Amino‐2‐Methoxymethylpyrrolidine (SAMP) and (<i>R</i>)‐(+)‐1‐Amino‐2‐Methoxymethylpyrrolidine (RAMP), Versatile Chiral Auxiliaries

Enders, Dieter; Fey, Peter; Kipphardt, Helmut

doi:10.1002/0471264180.os065.23

Cited by 14 publications

(15 citation statements)

References 6 publications

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“…General Procedure for the Preparation of Cyclic Hydrazimides 7 and 8: Cyclic hydrazimides 7 and 8 were prepared according to a reported procedure16 starting from ( S )‐1‐Amino‐2‐(methoxymethyl)pyrrolidine25 (3.91 g, 0.03 mol) and commercial glutaric anhydride (3.42 g, 0.03 mol) or adipic anhydride26 (3.84 g, 0.03 mol).…”

Section: Methodsmentioning

confidence: 99%

Asymmetric Synthesis of 2‐Heteroaryl Cyclic Amines: Total Synthesis of (–)‐Anabasine

et al. 2014

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Section: Methodsmentioning

confidence: 99%

Asymmetric Synthesis of 2‐Heteroaryl Cyclic Amines: Total Synthesis of (–)‐Anabasine

et al. 2014

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“…Means and standard errors of means are presented for untransformed data. 7,[10][11][12]14,19,[21][22][23][27][28]31,[33][34] were obtained from Aldrich Chemical, Milwaukee, Connecticut, USA and compounds 4-6, 8-9, 13, 15-18, 20, 24-26, 29-30, 32 were prepared from the O-alkylation of commercial compounds (Enders et al, 1987) (Fig. 1).…”

Section: Dmentioning

confidence: 99%

Response of Diabrotica speciosa (Coleoptera: Chrysomelidae) to 1,4-dimethoxybenzene and analogs in common bean crop

Marques

Wendler

Macedo

et al. 2009

Braz. arch. biol. technol.

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“…Melting points were determined on a Tottoli melting point apparatus and are uncorrected. The chiral auxiliaries SAMP and RAMP and the corresponding dioxanone hydrazones (S)-and (R)-2 were prepared from (S)-and (R)-proline according to literature procedures 12. …”

mentioning

confidence: 99%

“…MS (CI, 100 eV, methane): m/z (%) = 323 (57) [M + + 1], 305 (30), 289 (12), 287 (12), 247 (10), 215 (20), 213 (10), 173 (39), 157 (19), 145 (17), 143 (11), 131 (20), 129 (48), 119 (12), 91 (100), 83 (12).…”

mentioning

confidence: 99%

Asymmetric Synthesis of (S,S)- and (R,R)-2-Methylthreitol

Enders¹,

Peiffer²,

Raabe³

2007

Synthesis

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A s y m m e t r i c S y n t h e s i s o f ( S , S ) -a n d ( R , R ) -2 -M e t h y l t h r e i t o lAbstract: The asymmetric synthesis of (S,S)-and (R,R)-2-methylthreitol was carried out, starting from the SAMP or RAMP hydrazone of 2,2-dimethyl-1,3-dioxan-5-one. The protocol involves an enantioselective a-alkylation as a key step. The second stereogenic center was installed by either nucleophilic 1,2-addition or diastereoselective epoxidation with bis(acetylacetonato)oxovanadium(IV) [VO(acac) 2 ] as catalyst. The title compounds were obtained in excellent diastereo-and enantiomeric excesses (≥98% de, 98% ee) and in good overall yields (40-61%).(+)-2-Methylerythritol plays an important role in the mevalonate-free, methylerythritol phosphate (MEP) pathway for the biosynthesis of terpenoids in algae, plant chloroplasts, and Gram-negative bacteria. 1 This could be a starting point for the development of new microbe-inhibiting drugs. 2,3 Up to now the effect of the other stereoisomers on the MEP pathway are unknown. In addition, the tetrols occur in the atmosphere, mainly above the rainforest, where they act as condensation nuclei and scatter sunlight. 4 They arise by photooxidation of isoprene, leading to a mixture of all four stereoisomers. Up to now only (+)-2-methylerythritol 3,5 and (+)-2-methylthreitol 3 have been synthesized by asymmetric synthesis with moderate enantiomeric excess. Very recently, a chemo-enzymatic synthesis of all four isomers was published. 6 We envisaged a new diastereo-and enantioselective route to both enantiomers of the title 2-methylthreitol (1) based on a-hydroxymethylation of the SAMP-or RAMP-derived hydrazone of 2,2-dimethyl-1,3-dioxan-5-one [(S)-or (R)-2] 7 and a nucleophilic 1,2-addition to generate the quaternary stereocenter as key steps (Scheme 1). Scheme 1 Retrosynthetic analysis for 2-methylthreitolSAMP-derived hydrazone (S)-2, easily obtained in multigram quantities by condensation of the chiral auxiliary SAMP and the corresponding dioxanone, 8,9 was metalated with tert-butyllithium, and the azaenolate was trapped with (benzyloxy)methyl chloride (BOMCl) (Scheme 2). Acidic hydrazone cleavage 10 gave the a-[(benzyloxy)methyl]-substituted dioxanone (S)-3, obtained in 48% yield over two steps. Dioxanone (S)-3 was obtained in 98% ee (determined by CSP-GC analysis), indicating that the hydrazone alkylation occurred with virtually complete asymmetric induction and that the auxiliary was removed without any racemization. Next, ketone (S)-3 was reacted with methyllithium to afford the tertiary alcohol (S,S)-4 (Scheme 2), thus introducing the second and contiguous quaternary stereocenter. The nucleophilic 1,2-addition proceeded in good diastereoselectivity (84% de) and under optimized reaction conditions in 87% yield. The major diastereomer (S,S)-4 could be efficiently separated (in ≥98% de) from its diastereomeric impurity by preparative HPLC. Finally, two deprotection steps were performed to obtain (S,S)-2-methylthreitol [(S,S)-1] (Scheme 2). The acetonide function was hydrolyzed unde...

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(S)‐(−)‐1‐Amino‐2‐Methoxymethylpyrrolidine (SAMP) and (R)‐(+)‐1‐Amino‐2‐Methoxymethylpyrrolidine (RAMP), Versatile Chiral Auxiliaries

Cited by 14 publications

References 6 publications

Asymmetric Synthesis of 2‐Heteroaryl Cyclic Amines: Total Synthesis of (–)‐Anabasine

Asymmetric Synthesis of 2‐Heteroaryl Cyclic Amines: Total Synthesis of (–)‐Anabasine

Response of Diabrotica speciosa (Coleoptera: Chrysomelidae) to 1,4-dimethoxybenzene and analogs in common bean crop

Asymmetric Synthesis of (S,S)- and (R,R)-2-Methylthreitol

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