Stereospecific and stereoconvergent nucleophilic substitution reactions at tertiary carbon centers

نویسندگان

چکیده

The development of new reactions is important to improve the toolbox organic chemistry. One way nudge a reaction undergo pathway different from what it normally takes. Stereoinvertive SN2 known be intolerant bulky tertiary carbon centers, which tend proceed through SN1 pathways form racemized products. This leads long-standing challenge in synthesis; that is, how prepare enantiopure compounds substitution at centers. centers and via contact ion pair have been reported achieve this objective. Other strategies include stereoconvergent SN1, radical-nucleophilic substitution, halogen-bonding-assisted SN2X reactions. review discusses pathways. Understanding these unusual will inspire ways utilizing Nucleophilic substitutions such as are fundamental textbook Their stereoselective versions shown versatile preparation compounds. In review, we discuss challenges surrounding achieving stereoinvertive followed by discussions on using chiral-catalyst-directed radical-based nucleophilic Mechanistic provide insights can differentiated. occurs when an electrophile substituted nucleophile, displacing leaving group. Bimolecular (SN2) one most chemistry plays import role synthesis.1Hughes E.D. Ingold C.K. Scott A.D. 253. Reaction kinetics Walden inversion. Homogeneous hydrolysis, alcoholysis, ammonolysis ?-phenylethyl halides - Part II.J. Chem. Soc. 1937; 0: 1201-1208Crossref Scopus (19) Google Scholar,2Hughes Martin R.J.L. Meigh D.F. inversion unimolecular secondary alkyl halides.Nature. 1950; 166: 679-680Crossref PubMed (0) Scholar typical (Scheme 1A), nucleophile approaches center backside, group, usually halogen X, resulting go penta-coordinated transition state (TS) makes sensitive steric hindrance. Thus, challenging for electrophiles substitution. On other hand, able stabilized carbocations, favored (SN1) 1B). prochiral carbocation intermediates often lead products even enantio-enriched starting materials were used. Carbocation engage undesired side elimination rearrangement. Tertiary participate (SRN1) initiated single-electron transfer (SET) 1C).3Rossi R.A. Pierini A.B. Peñéñory electron transfer.Chem. Rev. 2003; 103: 71-167Crossref (390) SET step generates radical anion intermediate, undergoes C–X bond-breaking results radical. addition affords product. SRN1 under photochemical, electrochemical, thermal conditions. less hindrance highly reactive then result It possible atom bond approached halogenophilic (SN2X) 1D).4Zefirov N.S. Makhon’kov D.I. X-philic reactions.Chem. 1982; 82: 615-624Crossref (195) Scholar,5Sazonov P.K. Artamkina G.A. Beletskaya I.P. (halogenophilic reactions).Russ. 2012; 81: 317-335Crossref (26) Early reports date back 1930s. assisted bonding,6Bayse C.A. Rafferty E.R. Is bonding basis iodothyronine deiodinase activity?.Inorg. 2010; 49: 5365-5367Crossref (52) Scholar,7Zhang Y. halophilic reaction: A theoretical study.J. Mol. Struct. THEOCHEM. 961: 6-8Crossref (8) with rising research interests catalysis,8Cavallo G. Metrangolo P. Milani R. Pilati T. Priimagi A. Resnati Terraneo bond.Chem. 2016; 116: 2478-2601Crossref Scholar, 9Sutar R.L. Huber S.M. Catalysis bonding.ACS Catal. 2019; 9: 9622-9639Crossref (41) 10Benz S. Poblador-Bahamonde A.I. Low-Ders N. Matile pnictogen, chalcogen, bonds.Angew. Int. Ed. Engl. 2018; 57: 5408-5412Crossref studies revived after decades inactivity. polarized bond, density anisotropically distributed more electrons accumulate around forming belt high density. contrary, outermost region along lower becomes site ?-hole.11Lim J.Y.C. Beer P.D. Sigma-hole interactions recognition.Chem. 4: 731-783Abstract Full Text PDF (107) demanding environment may thus SN2X, insensitive compared SN2. synthesis approach stereospecific substitutions. congested formation 1E). described. Subsequently, chiral catalyst-directed racemic materials, proceeding carbocation, radical, carbanion also discussed.12Lucas E.L. Jarvo Stereospecific cross-couplings between electrophiles.Nat. 2017; 1: 65-72Crossref 13Cherney A.H. Kadunce N.T. Reisman S.E. Enantioselective enantiospecific transition-metal-catalyzed cross-coupling organometallic reagents construct C-C bonds.Chem. 2015; 115: 9587-9652Crossref 14Bhat V. Welin Guo X. Stoltz B.M. Advances catalysis 2005 2015: transition-metal-mediated stereoablative reactions, dynamic kinetic resolutions, asymmetric transformations.Chem. 117: 4528-4561Crossref (102) Comparison made factors determining discussed. We hope mechanistic help understand promoted utilized synthesis. previously regarded improbable substrates However, several groups since achieved adjacent electron-withdrawing (EWGs). These accelerated was newly developed methodologies. inverted configurations products, authors proposed underwent mechanism. Iwasa copper-catalyzed chlorination ?-keto esters affording various cyclic acyclic chlorides 2 2).15Shibatomi K. Soga Narayama Fujisawa I. Highly enantioselective subsequent s displacement chlorides: flexible method construction quaternary stereogenic centers.J. Am. 134: 9836-9839Crossref (87) two carbonyl groups, successfully nucleophiles, including sodium azides, alkylthiols, cesium fluorides. X-Ray analysis confirmed configuration corresponding amines 3, thioethers 4, fluorides 5 inverted, suggesting Jacobsen squaramide catalyst C2 silyl ketene acetals N-chlorosuccinimide (NCS) 3).16Liu R.Y. Wasa M. E.N. ?-chloro non-covalent catalysis.Tetrahedron Lett. 56: 3428-3430Crossref (23) ?-Chlorinated lactones 7 generated efficiently fluorides, alkylthiols. Corresponding azides 8, 9, 10 obtained. proven Park phase-transfer Maruoka C3 alkylation bromides 4).17Kim D. Ha M.W. Hong C. Kim B. Yang J. H.G. ?-azido ?-aryloxy phase-transfer-catalyzed ?-alkylation ?-bromomalonates, substitution.J. Org. 4936-4943Crossref (10) ?-Bromo-?-alkylmalonates 12 yield enantioselectivity. azide phenolic alcohols give ?-azido-?-alkylmalonates 13 ?-aryloxy- ?-allylmalonates 14 displacement. achieved. decarboxylative ?-ketocarboxylic acids amine C4 5).18Shibatomi Kitahara Sasaki Kawasaki acids.Nat. Commun. 8: 15600Crossref (30) 1,10-binaphthyl-based amino ester NCS chloride source. Carboxylic transformed ?-chloroketone 16, thiolates manner. discussed above modulated successful their Another group epoxides, susceptible ring opening due strain. Pericàs Riera acid derivatives key attack epoxides 6A).19Martín Islas Moyano M.A. N-Boc-?,?-disubstituted ?-amino acids.Tetrahedron. 2001; 6367-6374Crossref (40) epoxy-alcohol 19 easily prepared Sharpless epoxidation. Sodium azide, catalyzed mild Lewis acid, selectively add generate 20 Further situ hydrogenation protection gave N-Boc-3-amino-1,2-diols 21. another example, Grimme Gansäuer 6B).20Zhang Y.Q. Poppel Panfilova Bohle F. epoxides.Angew. 9719-9722Crossref (11) combination PhSiH3 tetrabutylammonium fluoride (TBAF) used active hydride epoxides. added 22, producing 1,3-diols 23 DFT calculation elucidated rather than sterically hindered carbon. H-C-O angle reaction, closer ideal 180o carbon, allowing better orbital overlap. gem-Dichlorooxirane, intermediate Corey-Link ring-opening nucleophiles. Pedregal modified bicyclic fluorinated 7A).21Pedregal Prowse W. Stereoselective 2-amino-3-fluoro bicyclo[3.1.0]hexane-2,6-dicarboxylic acid.Bioorg. Med. 2002; 10: 433-436Crossref (17) alcohol 25 trichloromethylcarbanion its ketone. Following deprotonation cyclization led gem-dichlorooxirane 26. Azide epoxide manner azido-acyl-chloride 27. quickly coupled azidoester 28 Similar carbohydrate 7B).22Sørensen M.H. Nielsen Synthesis analogue AZT restricted O4?-endo conformation.J. 66: 4878-4886Crossref (43) Scholar,23Forman G.S. Scaffidi Stick R.V. An alternative some acids.Aust. 2004; 25-28Crossref (12) Sato spiro-?-chloroepoxide 34, epoxidation ?-chloroolefin 33 meta-chloroperoxybenzoic (mCPBA). Several ?-azidoaldehydes obtained 8A).24Sato K.I. Sekiguchi Hozumi Yamazaki Akai Improved synthetic preparing spiro ?-chloroepoxides.Tetrahedron 43: 3087-3090Crossref Separately, Masaki ?-chloroepoxides 38 synthesized 36 8B).25Masaki Arasaki H. Iwata derivatives.Chem. 32: 4-5Crossref (28) or cyanide ?-azido-aldehyde 39a cyanohydrine 40a, respectively. When R configuration. Unexpectedly, phenyl retention explained double inversion; had occurred twice. ?-Chloroaldehyde 41 formed stirring ?-chloroepoxide room temperature h; cyanide, supported hypothesis. Vicinal diol sulfites sulfates epoxide-like synthons. common strategy further transformations. Many nucleophiles moieties, opening. demonstrated occur instead, provided there 9).26Shao Rueter J.K. Goodman Novel ?-methylthreonines ? ?-dimethylcysteines.J. 1998; 63: 5240-5244Crossref Scholar,27Avenoza Cativiela Corzana Peregrina J.M. Sucunza Zurbano M.M. (S)- (R)-?-methylserines: application (R)-N-Boc-N,O-isopropylidene-?-methylserinals.Tetrahedron Asymmetry. 12: 949-957Crossref Studies Avenoza showed sulfite 43 mixture azido 44 45, regioselectivity 1:4 favor ester. Alternatively, sulfate 46, oxidation 43. Acidic hydrolysis 47 48 retaining regioselectivity. suitable still challenging. many practical alcohols, them requires hydroxyl activated become good groups.28Räder A.F.B. Tiefenbacher SN2-like stereoinversion.Angew. 2014; 53: 1206-1207Crossref (7) Cyclic examples activation alcohols. report Cohen intramolecular chain quinone 49 10).29Cohen Lopresti R.J. Neukom total (2R,4’R,8’R)-?-Tocopherol (vitamin E). Cyclizations Leading Optically Active chromans.J. 1981; 46: 2445-2450Crossref (67) Excess methanesulfonyl mesylate 50 reduction dithionite, generating unstable hydroquinone 51. 51, not isolated, immediately treated hydroxide cyclized product 52. strong backside attack. Samuelsson fluorination cyclopentanol 53 carbocyclic nucleoside analogs 11A).30Wachtmeister Miihlman 4-substituted 2,3-dideoxy-3-C-hydroxymethyl analogues potential anti-viral agents.Tetrahedron. 1999; 55: 10761-10770Crossref (20) Deoxofluor reagent 55 containing hydroxy-thiolfluoroamine Fluoride released during Müller thionyl 11B).31Müller Rossier J.C. Solvent effects course solvolysis derivatives.J. Perkin Trans. 2000; 2: 2232-2237Crossref (25) 57 moderate 98% configuration, 58. 2003, Shi Group Merck Mitsunobu phenols diethyl azodicarboxylate (DIAD) triphenylphosphine (PPh3) 12A).32Shi Y.J. Hughes D.L. McNamara alkyl-aryl ethers complete configuration.Tetrahedron 44: 3609-3611Crossref (49) 60 pathway. conducted elevated required groups. McCarthy azido-Mitsunobu HN3 12B).33Green J.E. Bender D.M. Jackson O’donnell M.J. Mccarthy J.R. optically ?,?-disubstituted acids.Org. 2009; 11: 807-810Crossref (59) proceeded ambient temperatures 1,1-(azodicarbonyl)dipiperidine (ADDP) trimethylphosphine (PMe3). 63 Mukaiyama similar activate replacements 13).34Mukaiyama Shintou Fukumoto convenient tert-alkyl carboxylates tert-alcohols type oxidation-reduction condensation 2,6-dimethyl-1,4-benzoquinone.J. 125: 10538-10539Crossref (71) 35Shintou Efficient methods symmetrical unsymmetrical dialkyl condensation.J. 126: 7359-7367Crossref (101) 36Mukaiyama Ikegai aryl sulfides alkoxydiphenylphosphines condensation.Chem. 33: 1522-1523Crossref 37Masutani Minowa Hagiwara Cyanation cyanophosphonate 2,6-dimethyl-1,4-benzoquinone condensation.Bull. Jpn. 2006; 79: 1106-1117Crossref into diphenylphosphinite 69 base chlorodiphenylphosphine, quinone. 70 contains phosphanyloxy excellent making acids, phenols, degrees scope wide without need EWGs. Various method. Thiol thiol 75, but only Diethyl source converted isocyanide 76 Mechanistically, attractive seems unlikely fruitful carbocations prochiral. restriction circumvented use tight ion-pair interactions. Lewis-acid-promoted cationic intermediates. Shenvi scandium(III) triflate-catalyzed stereoinversion trimethylsilyl (TMSCN) N-centered 14).38Pronin S.V. Reiher Stereoinversion tertiary-alkyl isonitriles amines.Nature. 2013; 501: 195-199Crossref (80) isocyanides 78 yields level specific affecting unprotected primary hydroxy mechanism has fully investigated, Unlike both faces cation available incoming 77 face blocked counter anion. stereospecific. Similarly, Cook Baik iron-catalyzed 15A).39Marcyk P.T. Jefferies L.R. AbuSalim Pink S.P. unactivated tethered sulfonamides.Angew. 58: 1727-1731Crossref (16) By 80, sulfonamide indoline 81 Repo Samec 15B).40Watile Bunrit Margalef Akkarasamiyo Ayub Lagerspets E. Biswas J.S.M. Intramolecular chirality iron(III) catalyst.Nat. 3826Crossref (9) N-, O-, S-centered heterocycles 84 reported. They found dependent solvents low polarity, possibility pair. Marek recently 16).41Lanke stereocenters.J. 2020; 142: 5543-5548Crossref (4) Cyclopropyl carbinol 85 crowded Enantio-enriched bromides, chlorides, efficiently. cyclobutonium 87 proposed. Besides obtain Under carefully controlled conditions, intermediates, carbanion, directed catalysts allow electrophiles. poor stereoselectivities. With advances transition-metal organcatalysis, SN1-type catalysts.42Gualandi Mengozzi L. Cozzi P.G. enols enolates.Synthesis. 3433-3443Crossref Scholar,43Gualandi Rodeghiero Catalytic phosphoric Brønsted catalysts.Asian 7: 1957-1981Crossref (13) part, Proposed models 2004, titanium (IV)-complex-catalyzed ethers, Braun 17). There tertiary-alcohol-derived 88 allyltrimethylsilanes, 89 enantioselectivity.44Braun Kotter Titanium(IV)-catalyzed transformation allylation.Angew. 514-517Crossref (83) 13C NMR spectra complex (1:1 ratio) downfield shift carbinyl atom, polarization carbon–oxygen bond. Comparable chemical shifts observed presence TiF4. enantioconvergent process transformation. C5 enantiomers ether diastereomeric pairs. equilibrated carbenium ion. attacked allyltrimethylsilane distinctly faster unblocked face. All-carbon Watson

برای دانلود باید عضویت طلایی داشته باشید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Facile nucleophilic substitution at the C3a tertiary carbon of the 3a-bromohexahydropyrrolo[2,3-b]indole scaffold.

The synthesis of 3a-substituted hexahydropyrrolo[2,3-b]indole derivatives via nucleophilic substitution at the C3a position is reported. Nitrogen-, oxygen-, sulfur-, fluoro- and carbon-based nucleophiles have been employed, using both conventional organic solvents and ionic liquids. The C3a-substituted derivatives were obtained in good to excellent yields.

متن کامل

Nucleophilic substitution reactions of pyranose polytosylates.

The 2,3,4-tri-toluenesulfonate ester derivatives of the methyl pyranosides of l-arabinose, d-ribose, d-lyxose, and d-xylose have been prepared, and their substitution reactions with various nucleophiles have been examined. For arabinose, xylose, and ribose, highly regioselective monosubstitutions were observed with benzoate, nitrite, and azide anions. These reactions have led to short and simpl...

متن کامل

Nucleophilic substitution of bromonorbornenes and derivatives by electron transfer reactions.

The photoinitiated substitution reactions of anti-7-bromobenzonorbornadiene (5), its syn isomer 6, exo-anti-13-bromobenzocyclobutanorbornene (7), syn-7-bromonorbornene (8) and bromonorbornane (9) with Me(3)Sn(-) and Ph(2)P(-) anions, in liquid ammonia, are here informed to occur with good yields of substitution. The stereochemical outcome is discussed in terms of calculations with the B3LYP fun...

متن کامل

Nucleophilic Substitution Reactions of α-Bromoacetanilides with Benzylamines

Kinetic studies of the reactions of α-bromoacetanilides [YC6H4NHC(=O)CH2Br] with substituted benzylamines (XC6H4CH2NH2) have been carried out in dimethyl sulfoxide at 35.0 C. The Hammett plots for substituent (Y) variations in the substrate (log kN vs. σY) are biphasic concave upwards/downwards with breaks at Y = 4-Cl (σY = 0.23). The Hammett coefficients ρY and the cross-interaction constant ρ...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

ژورنال

عنوان ژورنال: Chem

سال: 2021

ISSN: ['2451-9308', '2451-9294']

DOI: https://doi.org/10.1016/j.chempr.2020.11.022