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1.
Sun Joo KimTae Hong Jeon Im Sook MinIn Su Kim Young Hoon Jung 《Tetrahedron letters》2012,53(28):3680-3682
A concise asymmetric total synthesis of (S)-dapoxetine from commercially available 3-chloropropiophenone is described. The key step includes a highly stereoselective amination of chiral benzylic ether, with the retention of stereochemistry, using chlorosulfonyl isocyanate. 相似文献
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[reaction: see text] The Prins reaction of a chiral alkylidene morpholinone derived from (1R,2S)-ephedrine and 3-methyl-2-oxobutanoic acid proceeds with good diastereoselectivity to generate a spiro bis-acetal. Lewis acid mediated diastereoselective reductive cleavage of the spiro acetal and subsequent removal of the ephedrine portion generates a alpha-hydroxy-gamma-methoxy carboxamide which is readily converted to (S)-(+)-pantolactone with high enantiomeric excess. 相似文献
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《Tetrahedron: Asymmetry》2006,17(5):860-866
The enzymatic resolution of 3-amino-3-phenylpropan-1-ol derivatives has been studied through acylation processes. Candida antarctica lipase A (CAL-A) has been identified as the best biocatalyst for the transesterification reaction of 3-amino-3-phenyl-1-tert-butyldimethylsilyloxy-propan-1-ol using ethyl methoxyacetate as acylating agent and tert-butyl methyl ether as solvent. This enzymatic study has allowed us to obtain a valuable intermediate for the production of (S)-dapoxetine, which has been synthesized in good overall yield and high enantiomeric excess. 相似文献
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For the development of novel endocannabinoid templates with potential resistance to hydrolytic and oxidative metabolism, we are targeting the bis-allylic carbons of the arachidonoyl skeleton. Toward this end, we recently disclosed the synthesis and preliminary biological data for the (13S)-methyl-anandamide. We report now the total synthesis of the (10S)- and (10R)-methyl-counterparts. Our synthetic approach is stereospecific, efficient, and provides the analogs without the need for resolution. Peptide coupling, P-2 nickel partial hydrogenation, and cis-selective Wittig olefination are the key steps. 相似文献
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《Tetrahedron: Asymmetry》1998,9(13):2285-2291
The important key intermediate of a 20(S)-camptothecin synthesis was prepared enantioselectively using an enzyme-catalyzed resolution. A commercially available papain was found to exhibit the highest enantioselectivity with moderate activity, and the (S)-enantiomer of 99% ee was obtained as the remaining substrate. 相似文献
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《Tetrahedron: Asymmetry》2007,18(23):2787-2790
The enantioselective synthesis of (R)- and (S)-1-amino-3-hydroxypropylphosphonic acid, the phosphonate analogues of (S)- and (R)-homoserine, has been accomplished in four steps and good overall yield starting from diethyl (3R,5R)- or (3S,5S)-5-(hydroxymethyl)-2-[(S)-1-phenylethyl]isoxazolidinyl-3-phosphonate, respectively. 相似文献
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We reported efficient enantioselective synthetic methodologies for (R)-alpha-alkylcysteines and (S)-alpha-alkylcysteines. The phase-transfer catalytic alkylation of 2-phenyl-2-thiazoline-4-carboxylic acid tert-butyl ester and 2-o-biphenyl-2-thiazoline-4-carboxylic acid tert-butyl ester, in the presence of chiral catalysts (1 or 2), gave the corresponding alkylated products, which could be hydrolyzed to provide (R)-alpha-alkylcysteines (67->99% ee) and (S)-alpha-alkylcysteines (66-88% ee), respectively. 相似文献
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The first enantioselective total synthesis of the bisanthraquinone (S)-bisoranjidiol and an unnatural regioisomer has been accomplished. Key features of the synthesis include the asymmetric oxidative biaryl coupling of a hindered 8-substituted 2-naphthol, selective para-quinone formation, and regioselective tandem Diels-Alder/aromatization reactions. 相似文献
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An imidazolidin-2-one chiral auxiliary mediated acetate aldol reaction was explored in the enantioselective synthesis of (S)-dapoxetine (SSRI). The diastereoselective aldol adduct was transformed to highly enantiopure (S)-dapoxetine with overall good yield. 相似文献
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A short, enantioselective synthesis of (-)-pentalenene is described. Catalytic enantioselective cyclopropenation with (R,R)-Rh2(OAc)(DPTI)3 was used to set the absolute stereochemistry, and an intramolecular Pauson-Khand reaction of the resulting cyclopropenyne was used to establish the quaternary center. 相似文献
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The first enantioselective synthesis of (-)-paeonilide is reported. Starting from inexpensive furan-3-carboxylic acid the targeted monoterpene was obtained in 12 steps via an asymmetric cyclopropanation-lactonization cascade and a stereoselective side chain insertion at an acetal-like position. 相似文献
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《Tetrahedron: Asymmetry》2006,17(11):1738-1742
An efficient enantioselective synthesis of (S,S)-ethambutol, a tuberculostatic antibiotic, has been achieved in 99% ee via both proline-catalyzed α-aminooxylation and α-amination of n-butyraldehyde as the key step. 相似文献
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The enantioselective total synthesis of the nonacyclic polypyrrolidinoindoline (−)-idiospermuline is described. Stereocontrolled formation of the vicinal quaternary carbon centers is achieved in a single step by dialkylation of an unsymmetrical prostereogenic dienolate with a tartrate-derived chiral dielectrophile. A catalyst-controlled diastereoselective Heck cyclization is employed to form the diaryl-substituted quaternary center. 相似文献
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Basiliskamide A is an antifungal polyketide natural product isolated by Andersen and co-workers from a Bacillus laterosporus isolate, PNG-276. A nine-step enantioselective synthesis of (-)-basiliskamide A is reported, starting from commercially available β-hydroxy ester 7. The synthesis features a highly diastereoselective mismatched double asymmetric δ-stannylallylboration reaction of aldehyde 5 with the bifunctional allylborane reagent 4. 相似文献
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《Tetrahedron: Asymmetry》2001,12(14):2005-2008
An efficient enantioselective route to (S)-salmeterol involving asymmetric reduction of an azidoketone intermediate to an azido alcohol by Pichia angusta is described. 相似文献
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A concise enantioselective synthesis of (S)-homocitric acid lactone and its homolog, via an organocatalytic vinylogous Mukaiyama–Michael reaction of a silyloxy furan derivative and acrolein, is described. 相似文献