- Sodium Arenesulfinates-Involved Sulfinate Synthesis Revisited: Improved Synthesis and Revised Reaction Mechanism
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Reaction of alcohols with sodium arenesulfinates could afford either sulfones or sulfinates, and O-attack of sulfinate anions onto the in situ generated carbocation intermediates from alcohols was the previous proposed reaction mechanism in many syntheses of sulfinates. This concept, which is often used consciously or unconsciously, was revised herein by using isotopic labeling experiments and development of an improved sulfinate synthesis. The improved sulfinate synthetic protocol possesses many advantages such as a high sulfinate/sulfone selectivity, a broad substrate scope, metal-free, and mild reaction conditions. The revised reaction mechanism necessitates revision of many previous proposed reaction mechanisms in literatures.
- Ji, Yuan-Zhao,Li, Hui-Jing,Zhang, Jin-Yu,Wu, Yan-Chao
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p. 1846 - 1855
(2019/02/14)
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- Synthesis of nonracemic α-trifluoromethyl α-amino acids from sulfinimines of trifluoropyruvate
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We describe a novel and useful method for the synthesis of nonracemic α-trifluoromethyl α-amino acids (α-Tfm-AAs). Key building blocks are the sulfinimines (S)-1a and (S)-1b, prepared by Staudinger reaction from trifluoropyruvate esters and the chiral N-sulfinyl iminophosphorane (S)-8, which were treated with benzyl, allyl, and alkylmagnesium halides. The resulting diastereomeric N-sulfinyl α-Tfm α-amino esters, 12 and 13, were produced with moderate to good stereoselectivity and yields. When alkyl Grignard reagents were used, stereocontrol became progressively higher with increasing steric bulk, while reversed, though poor, stereocontrol was achieved with benzyl/allyl Grignard reagents. An explanation for the observed stereochemical outcome is proposed, on the basis of the exclusive E geometry (N-sulfinyl and CF3 trans about the C=N bond) of the chiral sulfinimines 1. This assignment is the product of structural correlation and is supported by ab initio calculations and NOE experiments. Sulfinamides 12 and 13 were transformed into a series of nonracemic α-Tfm-AAs 16-22. The sulfinyl auxiliary can be regenerated and recycled.
- Asensio, Amparo,Bravo, Pierfrancesco,Crucianelli, Marcello,Farina, Alessandra,Fustero, Santos,Soler, Juan García,Meille, Stefano V.,Panzeri, Walter,Viani, Fiorenza,Volonterio, Alessandro,Zanda, Matteo
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p. 1449 - 1458
(2007/10/03)
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- Highly diastereoselective synthesis and easy method for synthesis of optically active sulfinate esters from aromatic disulfides
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One-step synthesis of chiral aromatic sulfinate esters 2 from aromatic disulfides 1 using lead tetraacetate is reported. The yields are good to excellent and diastereoselectivity is high.
- Hajipour,Islami
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p. 536 - 538
(2007/10/03)
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- Enantioselective synthesis of haminol-1, an alarm pheromone of a Mediterranean mollusc
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The first enantioselective synthesis of (-)-(R)-haminol-1 is described in this paper. The chiral part of the molecule was prepared by reduction of an optically active β-ketosulfoxide. The all-trans trienic part was stereoselectively synthesized via reductive elimination of a 1,6-dibenzoate-2,4-diene with sodium amalgam.
- Solladie, Guy,Somny, Frederic,Colobert, Francoise
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p. 801 - 810
(2007/10/03)
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- Synthesis of Optically Active α-Alkylidene-β-hydroxy-γ-methylenebutyrolactones. Isoobtusilactones and Isomahubalactones (Isomahubanolide and Isomahubenolide)
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The title compounds were prepared via stereoselective aldol reaction of α,β-unsaturated carboxylate α-anion equivalent, derived from optically active α-(arylsulfinyl)carboxylate and bromomagnesium diisopropylamide, with propargyl aldehyde as a key step.
- Nokami, Junzo,Ohtsuki, Hirotoshi,Sakamoto, Yasuhuko,Mitsuoka, Masayuki,Kunieda, Norio
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p. 1647 - 1650
(2007/10/02)
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- O-sulfinylation with methanesulfonyl cyanide or p-toluenesulfonyl cyanide and DBU
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Reaction of methanesulfonyl cyanide or p-toluenesulfonyl cyanide with alcohols in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) gives sulfinates in good yield. A mechanistic scheme involving sulfinyl cyanates is suggested.
- Barton,Jaszberenyi,Theodorakis
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p. 2585 - 2588
(2007/10/02)
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- SYNTHESIS OF POTENTIALLY ALLERGENIC CHIRAL α-(HYDROXYALKYL)ACRYLATES
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The title componds have been synthesized with 75percent enantiomeric excess from chiral p-tolylsulfoxides 1 and aldehydes, followed by thermal elimination of the sulfoxide.
- Papageorgiou, Christos,Benezra, Claude
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p. 1303 - 1306
(2007/10/02)
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- SYNTHESES ASYMETRIQUES DE β-HYDROXYACIDES PAR CONDENSATION D'ANIONS ENOLATES D'ESTERS α-SULFINYLE CHIRAUX SUR DES COMPOSES CARBONYLES
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A stereospecific synthesis of (R)-(+)-t-butyl p-tolylsulfinyl acetate 2 is described.The aldol-type condensation of this reagent leads to β-hydroxyacids in good chemical and optical yields.The determination of the absolute configuration of the condensatio
- Mioskowski, Charles,Solladie, Guy
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p. 227 - 236
(2007/10/02)
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- Novel One-Step Preparation of Sulfinic Acid Derivatives from Sulfinic Acid
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Convenient one-step syntheses of sulfinamides and sulfinate esters from sulfinic acids were achieved by using coupling reagents, such as 2-chloro-1-methylpyridinium iodide, γ-saccharine chloride, N,N'-dicyclohexylcarbodiimide, and diethyl azodicarboxylate and triphenylphosphine.Ammonolysis of sulfinate esters also give sulfinamides.Keyword- sulfinic acid; sulfinamide; sulfinate ester; sulfinyl-transfer reagent; coupling reaction; 2-chloro-1-methylpyridinium iodide; γ-saccharine chloride; N,N'-dicyclohexylcarbodiimide; diethyl azodicarboxylate; triphenylphosphine
- Furukawa, Mitsuru,Ohkawara, Tadashi,Noguchi, Yoshihide,Nishikawa, Masumi,Tomimatsu, Masahide
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p. 134 - 141
(2007/10/02)
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