- Decarboxylative Conjunctive Cross-coupling of Vinyl Boronic Esters using Metallaphotoredox Catalysis
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The synthesis of complex alkyl boronic esters through conjunctive cross-coupling of vinyl boronic esters with carboxylic acids and aryl iodides is described. The reaction proceeds under mild metallaphotoredox conditions and involves an unprecedented decarboxylative radical addition/cross-coupling cascade of vinyl boronic esters. Excellent functional-group tolerance is displayed, and application of a range of carboxylic acids, including secondary α-amino acids, and aryl iodides provides efficient access to highly functionalized alkyl boronic esters. The decarboxylative conjunctive cross-coupling was also applied to the synthesis of sedum alkaloids.
- Aggarwal, Varinder K.,Duong, Vincent K.,Mega, Riccardo S.,Noble, Adam
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supporting information
p. 4375 - 4379
(2020/02/11)
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- Synthesis of (+)-dumetorine and congeners by using flow chemistry technologies
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An efficient total synthesis of the natural alkaloid (+)-dumetorine by using flow technology is described. The process entailed five separate steps starting from the enantiopure (S)-2- (piperidin-2-yl)ethanol 4 with 29 % overall yield. Most of the reactio
- Riva, Elena,Rencurosi, Anna,Gagliardi, Stefania,Passarella, Daniele,Martinelli, Marisa
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supporting information; experimental part
p. 6221 - 6226
(2011/06/26)
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- Enantioselective Synthesis of (+)-α-Conhydrine and (-)-Sedamine by L-ProlineCatalysed α-Aminooxylation
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An efficient organocatalytic approach to the enantioslective synthesis of two important piperidine alkaloids, namely (+)α-conhydrine (98% ee) and (-)-sedamine (95 % ee), by L-pro-line-catalysed α-aminooxylation of aldehydes has been developed. The strategy involves an intramolecular cyclization to construct the piperidine core.
- Shaikh, Tanveer Mahamadali,Sudalai, Arumugam
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experimental part
p. 3437 - 3444
(2010/08/20)
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- A rapid access to (±)-sedamine and some original N -benzyl unsaturated analogues
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Reduction of N-alkyl-2-(2-hydroxy-2-phenylethyl)pyridinium salts using excess of sodium triacetoxyborohydride afforded exclusively the corresponding tetrahydropyridine derivative bearing a piperidine ring with a double bond in the 3,4-position. Furthermore, under these conditions, syn-1,3-amino alcohols were obtained in good yield and diastereoselectivity. Georg Thieme Verlag Stuttgart · New York.
- Boussonniere, Anne,Ranaivondrambola, Tsiresy,Lebreton, Jacques,Mathe-Allainmat, Monique
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experimental part
p. 2456 - 2462
(2010/09/04)
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- Hydroformylation of homoallylic azides: A rapid approach toward alkaloids
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(Chemical Equation Presented) Unprecedented hydroformylation of homoallylic azides combined with useful one-pot operations provides an expeditive access to alkaloids.
- Spangenberg, Thomas,Breit, Bernhard,Mann, Andre
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supporting information; experimental part
p. 261 - 264
(2009/08/08)
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- Pd-catalyzed enantioselective aerobic oxidation of secondary alcohols: Applications to the total synthesis of alkaloids
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Enantioselective syntheses of the alkaloids (-)-aurantioclavine, (+)-amurensinine, (-)-lobeline, and (-)- and (+)-sedamine are described. The syntheses demonstrate the effectiveness of the Pd-catalyzed asymmetric oxidation of secondary alcohols in diverse contexts and the ability of this methodology to set the absolute configuration of multiple stereocenters in a single operation. The utility of an aryne C-C insertion reaction in accessing complex polycyclic frameworks is also described.
- Krishnan, Shyam,Bagdanoff, Jeffrey T.,Ebner, David C.,Ramtohul, Yeeman K.,Tambar, Uttam K.,Stoltz, Brian M.
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supporting information; experimental part
p. 13745 - 13754
(2009/02/06)
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- Synthesis of sedamine by cycloisomerisation of an allenic hydroxylamine
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Isoxazolidines have been prepared in a stereoselective manner by treatment of allenic hydroxylamines with silver(I). This methodology has been used in a short synthesis of the alkaloid (+)-sedamine. Georg Thieme Verlag Stuttgart.
- Bates, Roderick W.,Nemeth, Joseph A.,Snell, Robert H.
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p. 1033 - 1038
(2008/12/22)
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- Enantioselective synthesis of lobeline via nonenzymatic desymmetrization
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Lobeline has been prepared in enantiopure form via desymmetrization of lobelanidine with use of BTM, a nonenzymatic enantioselective acyl transfer catalyst.
- Birman, Vladimir B.,Jiang, Hui,Li, Ximin
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p. 3237 - 3240
(2008/02/11)
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- An efficient approach to 2-substituted N-tosylpiperdines: asymmetric synthesis of 2-(2-hydroxy substituted)piperidine alkaloids
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We have developed an efficient and a general approach to chiral 2-substituted N-tosylpiperidines starting from chiral α-substituted-N-tosylaziridines. Using this approach, we have synthesized (+)-coniine. The synthesis of chiral N-tosyl-2-piperidinylethanol 15 and ent-15, was achieved from l- and d-aspartic acids, respectively in few steps. Piperidine 15 was converted into 2-(2-hydroxysubstituted)piperidines of type 2 in optically active form. By applying this strategy, asymmetric syntheses of halosaline (R,R)-2a, (+)- and (-)-sedamine 2b, (+)- and (-)-allosedamine 2c, (+)- and (-)-sedridine 2d, (+)- and (-)-allosedridine 2e, (+)-tetraponerine T-3 3a, T-4 3c, T-7 3b, and T-8 3d have been achieved in high yields. These stereoisomers can be interconverted via Mitsunobu inversion in excellent yields.
- Bisai, Alakesh,Singh, Vinod K.
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p. 1907 - 1910
(2007/10/03)
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- Stereoselective synthesis of anti-1,3-diol units via Prins cyclisation: application to the synthesis of (-)-sedamine
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The scope of the Prins cyclisation, the higher stereoselective synthesis of multisubstituted tetrahydropyrans from aldehydes and homoallylic alcohols, is expanded. A new approach for the stereoselective synthesis of polyketide precursors containing anti-1
- Yadav,Reddy, M. Sridhar,Rao, P. Purushothama,Prasad
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p. 4397 - 4401
(2007/10/03)
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- Indirect trapping of the retroconjugate addition reaction intermediate involved in the epimerization of lobeline: Application to the synthesis of (-)-sedamine
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Alkyl chloroformates induced indirect trapping of the retroconjugate addition reaction intermediate involved in the epimerization of lobeline is described. This strategy was applied to the conversion of (-)-lobeline to (-)-sedamine in high overall yield.
- Zheng, Guangrong,Dwoskin, Linda P.,Crooks, Peter A.
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p. 8514 - 8517
(2007/10/03)
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- Remote Stereocenter Discrimination in the Enzymatic Resolution of Piperidine-2-ethanol. Short Enantioselective Synthesis of Sedamine and Allosedamine
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Kinetic resolution of N-Boc-piperidine-2-ethanol (2), a case of remote stereocenter discrimination, was accomplished by sequential transesterification mediated by two enzymes, Lipase PS and porcine pancreatic lipase, showing opposite enantioselectivity. The gram-scale availability of the two enantiomeric N-Boc alcohols 2a (R) and 2c (S) enlarges their synthetic exploitation for the enantioselective preparation of piperidine alkaloids. As an example, the convenient three-step synthesis of both the enantiomers of sedamine and allosedamine is described.
- Angoli, Marco,Barilli, Alessio,Lesma, Giordano,Passarella, Daniele,Riva, Sergio,Silvani, Alessandra,Danieli, Bruno
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p. 9525 - 9527
(2007/10/03)
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- A highly stereoselective asymmetric synthesis of (-)-lobeline and (-)-sedamine
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A highly stereoselective asymmetric synthesis of (-)-sedamine and (-)-lobeline is described from benzaldehyde in 16 and 17 steps with an overall yield of 20% and 14%, respectively. The key intermediate syn-3,4-epoxyalcohol was prepared in a highly diastereomeric fashion (>99% ee, dr) and served as a common intermediate for both alkaloids.
- Felpin, Francois-Xavier,Lebreton, Jacques
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p. 9192 - 9199
(2007/10/03)
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- A concise synthesis of homochiral sedamines and related alkaloids. A new reductive application of Jacobsen's catalyst
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Two methods for the generation of both enantiomers of sedamine [1- methyl-2-(2-phenyl-2-hydroxy-1-ethyl)piperidine] in high optical purity have been elaborated. The first utilises the lipase-mediated kinetic resolution of racemic acetates and the second involves the NaBH4 mediated reduction of ketones catalysed by Jacobsen's catalyst. Some related applications of these reactions are also disclosed.
- Yu, Chu-Yi,Meth-Cohn, Otto
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p. 6665 - 6668
(2007/10/03)
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- An applied stereocontrolled synthesis of piperidine derivative utilizing diastereoselective reaction of chiral 1,3-oxazolidine with grignard reagent; Asymmetric synthesis of an alkaloid, (-) sed amine
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A facile total synthesis of enantiomerically pure (-)-sedamine, known as a naturally occurring alkaloid, was accomplished by use of the diastereo-selective addition of Grignard reagent to a chiral 1,3-oxazolidine, and utilizing of 1-aza-4-oxabicyclo[4.3.0
- Poerwono, Hadi,Higashiyama, Kimio,Takahashi, Hiroshi
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p. 263 - 270
(2007/10/03)
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- The Addition of Metallo Enolates to Chiral 1-Acylpyridinium Salts. An Asymmetric Synthesis of (-)-Sedamine
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Synthetically useful 2-(2-oxoalkyl)-2,3-dihydro-4-pyridones are prepared in high diastereomeric excess by addition of ketone metallo enolates to chiral 1-acyl-4-methoxypyridinium salts.
- Comins, Daniel L.,Hong, Hao
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p. 5035 - 5036
(2007/10/02)
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- Trimethylsilyl trifluoromethanesulfonate (TMSOTf) catalyzed amidoalkylation of silylenolethers. Stereocontrolled syntheses of (+/-)-sedamine and (+/-)-norsedamine
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Trimethylsilyl trifluoromethanesulfonate (TMSOTf) catalyzed addition of 1-trimethylsilyloxy-1-phenylethene to N-ethoxycarbonyl- and N-tert-butoxycarbonyl-2-ethoxypiperidines (3a and 3b, respectively) afforded the corresponding ketocarbamates 4a and 4b, in excellent yields. Stereoselective conversion to (±)-norsedamine (7) and (±)-sedamine (8) is described.
- Pilli,Dias
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p. 2213 - 2229
(2007/10/02)
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- A FACILE SYNTHESIS OF dl-SEDAMINE AND dl-ALLOSEDAMINE
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Racemic sedamine and dl-allosedamine were easily synthesized from the intermediate (3) using a cyclic acyliminium salt by the addition-elimination reaction sequence.
- Ozawa, Naganori,Nakajima, Setsuko,Zaoya, Kyoko,Hamaguchi, Fumiko,Nagasaka, Tatsuo
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p. 889 - 894
(2007/10/02)
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- ASYMMETRIC SYNTHESIS OF (+)- AND (-)-CONIINES AND (-)-SEDAMINE BY DIASTEREOSELECTIVE ALKYLATION REACTION OF ETHOXYPIPERIDININE
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Diastereoselective alkylation reaction of the chiral 6-ethoxypiperidinones (4) and (5) has been developed and successfully applied to the asymmetric synthesis of piperidine alkaloids, (+)- and (-)-coiines (11) and (12), (-)-sedamine (21), and (-)-allosedamine (22).
- Kiguchi, Toshiko,Nakazono, Yoko,Kotera, Sanae,Ninomiya, Ichiya,Naito, Takeaki
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p. 1525 - 1535
(2007/10/02)
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- Stereochemistry of the Intermolecular and Intramolecular Conjugate Additions of Amines and Anions to Chiral (E)- and (Z)-Vinyl Sulfoxides. Total Syntheses of (R)-(+)-Carnegine and (+)- and (-)-Sedamine
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The intramolecular addition of incipient amine anions to chiral (E)- and (Z)-vinyl sulfoxides occurs in the same diastereofacial sense, giving chiral isoquinoline and piperidine derivatives that differ in relative stereochemistry at C-2.In contrast, the conjugate addition reactions of (E)- and (Z)-β-styryl p-tolyl sulfoxide wih benzylamine and LiCH(CO2Et)2 are diastereoconvergent processes.The same major diastereomeric product is obtained in each case.We have attempted to rationalize the stereochemical outcome of the addition of nucleophiles to chiral vinyl sulfoxides according to the type of nucleophilic reagent employed (either chelating/hydrogen bonding or nonchelating) and from a consideration of possible transition states.
- Pyne, Stephen G.,Bloem, Peter,Chapman, Sandra L.,Dixon, Christine E.,Griffith, Renate
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p. 1086 - 1093
(2007/10/02)
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- THE CYCLOADDITION REACTION BETWEEN STYRENE AND 2,3,4,5-TETRAHYDROPYRIDINE 1-OXIDE
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The cycloaddition of styrene to 2,3,4,5-tetrahydropyridine 1-oxide leads, with a high yield, to a 97:3 mixture of the diastereoisomeric isoxazolidines 3c and 4c respectively.
- Hootele, C.,Ibebeke-Bomangwa, W.,Driessens, F.,Sabil, S.
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