1693-83-0Relevant academic research and scientific papers
Chiral Br?nsted-Acid-Catalyzed Asymmetric Oxidation of Sulfenamide by Using H2O2: A Versatile Access to Sulfinamide and Sulfoxide with High Enantioselectivity
Ma, Long-Jun,Chen, Shu-Sen,Li, Guang-Xun,Zhu, Jin,Wang, Qi-Wei,Tang, Zhuo
, p. 1525 - 1530 (2019)
Herein, we describe an example of catalytic asymmetric synthesis of sulfinamides. Aromatic sulfenamides were chosen as useful substrates, because of the indispensable N-H bond, which could form an efficient hydrogen bond with chiral phosphoric acid. Hsub
Stereoselective synthesis of isoindolinones and tert-butyl sulfoxides
Kaw?cki, Robert,Stańczyk, Wojciech,Jaglińska, Agnieszka
, p. 578 - 584 (2017/12/28)
A reaction of Grignard reagents with an optically pure N-sulfinylimine derived from methyl 2-formylbenzoate yields enantioenriched isoindolinones and tert-butyl sulfoxides. The products are formed by the addition of the nucleophile to N-sulfinylimine followed by cyclization to form N-tert-butylsulfinylisoindolinone, which readily undergoes substitution with a second equivalent of Grignard reagent. The reaction can be carried out in dichloromethane at room temperature or at elevated temperatures without any loss of stereoselectivity. The use of nucleophiles other than Grignard reagents has also been investigated.
Investigation of functionalized α-chloroalkyllithiums for a stereospecific reagent-controlled homologation approach to the analgesic alkaloid (-)-epibatidine
Emerson, Christopher R.,Zakharov, Lev N.,Blakemore, Paul R.
supporting information, p. 16342 - 16356 (2013/12/04)
Four putative functionalized α-chloroakyllithiums RCH 2CHLiCl, where R=CHCH2 (18 a), CCH (18 b), CH 2OBn (18 c), and CH[O(CH2)2O] (18 d), were generated in situ by sulfoxide-lithium exchange from α-chlorosulfoxides, and investigated for the stereospecific reagent-controlled homologation (StReCH) of phenethyl and 2-chloropyrid-5-yl (17) pinacol boronic esters. Deuterium labeling experiments revealed that α-chloroalkyllithiums are quenched by proton transfer from their α-chlorosulfoxide precursors and it was established that this effect compromises the yield of StReCH reactions. Use of α-deuterated α-chlorosulfoxides was discovered to ameliorate the problem by retarding the rate of acid-base chemistry between the carbenoid and its precursor. Carbenoids 18 a and 18 b showed poor StReCH efficacy, particularly the propargyl group bearing carbenoid 18 b, the instability of which was attributed to a facile 1,2-hydride shift. By contrast, 18 d, a carbenoid that benefits from a stabilizing interaction between O and Li atoms gave good StReCH yields. Boronate 17 was chain extended by carbenoids 18 a, 18 b, and 18 d in 16, 0, and 68 % yield, respectively; α-deuterated isotopomers D-18 a and D-18 d gave yields of 33 and 79 % for the same reaction. Double StReCH of 17 was pursued to target contiguous stereodiads appropriate for the total synthesis of (-)-epibatidine (15). One-pot double StReCH of boronate 17 by two exposures to (S)-D-18 a (≤66 % ee), followed by work-up with KOOH, gave the expected stereodiad product in 16 % yield (d.r.～67:33). The comparable reaction using two exposures to (S)-D-18 d (≤90 % ee) delivered the expected bisacetal containing stereodiad (R,R)-DD-48 in 40 % yield (≥98 % ee, d.r.=85:15). Double StReCH of 17 using (S)-D-18 d (≤90 % ee) followed by (R)-D-18 d (≤90 % ee) likewise gave (R,S)-DD-48 in 49 % yield (≥97 % ee, d.r.=79:21). (R,S)-DD-48 was converted to a dideuterated isotopomer of a synthetic intermediate in Corey's synthesis of 15. Copyright
Desymmetrization of prochiral diaryl sulfoxides by an asymmetric sulfoxide-magnesium exchange
Hampel, Thomas,Ruppenthal, Simon,Saelinger, Daniel,Brueckner, Reinhard
supporting information; experimental part, p. 3136 - 3140 (2012/05/20)
The first desymmetrizations of prochiral diaryl sulfoxides 1 by an asymmetric sulfoxide-magnesium exchange reaction are reported. The respective substrate (1), iPr2Mg, and the dilithium salt of (S)-BINOL (which was prepared in situ) provided (S)-configured aryl isopropyl sulfoxides 2 in up to 91 % yield and with up to 91 % ee. (S)-BINOL was re-isolable in 98 % yield. Copyright
BINOL derived C2-symmetric bis-sulfinates as efficient sulfinyl transfer agents in the synthesis of tert-butyl sulfoxides
Gaggero,Albanese
experimental part, p. 7129 - 7132 (2012/09/05)
The reaction of novel C2-symmetric bis-sulfinate esters derived from (R)-BINOL with Grignard reagents affords tert-butyl sulfoxides in ee up to 97%. The desired enantiomer can be generated at will by the proper selection of BINOL.
Towards a flexible strategy for the synthesis of enantiomerically pure [2.2]paracyclophane derivatives: The chemistry of 4-tolylsulfinyl[2.2] paracyclophane
Parmar, Rakesh,Coles, Martyn P.,Hitchcock, Peter B.,Rowlands, Gareth J.
experimental part, p. 4177 - 4187 (2011/02/25)
The use of enantiomerically enriched 4-tolylsulfinyl[2.2]paracyclophane as a precursor to a variety of mono- and di-substituted [2.2]paracyclophane derivatives is described. The goal of our research is to develop a single general precursor that permits the synthesis of the most common [2.2]paracyclophane substitution patterns. The chemistry of two diastereoisomers of 4-tolylsulfinyl[2.2]paracyclophane has been explored and it facilitates the synthesis of enantiomerically enriched 4-substituted and 4,13-disubstituted [2.2]paracyclophanes. Directed lithiations result in an unusual cyclisation reaction. Whilst the tolyl group cannot realise our goal, the chemistry outlined acts as a successful proof of concept.
Diastereomeric sulfinates derived from (L)-N-methylephedrine: Synthesis, applications and rearrangements
Drabowicz, Jozef,Bujnicki, Bogdan,Biscarini, Paolo,Mikolajczyk, Marian
, p. 3177 - 3187 (2007/10/03)
The reaction of sulfinyl chlorides with (L)-N-methylephedrine alone or in the presence of tertiary amines was found to produce diastereomeric sulfinates with diastereomeric purities up to 90%. The diastereomeric ratio is strongly influenced by the nature
Titanium-Catalyzed, Asymmetric Sulfoxidation of Alkyl Aryl Sulfides with Optically Active Hydroperoxides
Adam, Waldemar,Korb, Marion N.,Roschmann, Konrad J.,Saha-Moeller, Chantu R.
, p. 3423 - 3428 (2007/10/03)
The Ti-catalyzed, asymmetric oxidation of alkyl aryl sulfides by enantiomerically pure hydroperoxides (ee >99%) has been examined. Enantioselectivities with ee values up to ca. 80% were achieved for the oxygen transfer from (S)-(-)-1-phenylethyl hydroperoxide 2a to methyl phenyl and methyl p-tolyl sulfide 1a in CCl4 as solvent, but with much overoxidation to the corresponding sulfone 4. Detailed mechanistic studies showed that the enantioselectivity of the sulfide 1a oxidation results from a combination of a rather low (ee values >20%) asymmetric induction in the sulfoxidation and an effective kinetic resolution (ee values ca. 80% at 85% sulfide conversion) of the sulfoxide 3a by enantioselective oxidation to the sulfone 4a. The overoxidation (loss of chemoselectivity) is due to sulfoxide coordination to the Ti metal to generate a template in which the oxygen atom is intramolecularly transferred from the bound and activated, optically active hydroperoxide to the ligated sulfoxide in a stereocontrolled manner.
Asymmetric synthesis of chiral organosulfur compounds using N-sulfinyloxazolidinones
Evans, David A.,Faul, Margaret M.,Colombo, Lino,Bisaha, John J.,Clardy, Jon,Cherry, David
, p. 5977 - 5985 (2007/10/02)
This paper describes a new class of chiral sulfinyl transfer reagents, 4 and 5 (R = aryl, alkyl), which are readily prepared from the oxazolidinones derived from (4R,5S)-norephedrine (HXN) and (4S)-phenylalanine (HXp), respectively. These N-suIfinyloxazolidinone reagents can be synthesized either by sulfinylation-of the metalated oxazolidinones or by oxidation of the derived N-sulfenimides to afford the diastereomeric N-sulfinyloxazolidinones which may be readily purified by chromatography. These sulfinylating agents react with a wide range of nucleophiles such as Grignard reagents, enolates, lithium alkoxides, or metalated amides, with inversion of configuration at the sulfur center to afford the derived chiral sulfoxides, sulfinate esters, and sulfinamides in high yields and enantioselectivities. Competition experiments have established that this family of chiral sulfinylating agents is at least 100 times as reactive as the corresponding menthyl sulfinate esters toward Grignard reagents.
ORGANOSULPHUR COMPOUNDS-LXIX OPTICALLY ACTIVE SULPHINATES: A NEW TYPE OF ENANTIOSELECTIVE ASYMMETRIC SYNTHESIS AND KINETIC RESOLUTION
Drabowicz, Jozef,Legedz, Slawomir,Mikolajczik, Marian
, p. 5243 - 5252 (2007/10/02)
Optically active sulphinates with the sulphur atom as a sole centre of chirality are prepared by two methods.The first involves the reaction of symmetrical sulphites with tert-butylmagnesium chloride in the presence of optically active aminoalcohols.This new asymmetric, enantioselective synthesis affords t-butylsulphinates with 40-70percent enantiomeric excess values.The second approach is based on a new type of kinetic resolution taking place when racemic sulphinates are reacted with tert-butylmagnesium chloride complexed by optically active alkaloid bases.Both the recovered sulphinates and sulphoxides formed in this reaction show moderate optical purities.
