1470-91-3Relevant academic research and scientific papers
Facile synthesis of fluorovinyl-containing lactams via ring-closing metathesis of N-substituted 2-fluoroallylamides
Li, Yang,Li, Kai,Wu, Yue,Ma, Qiaoning,Lei, Xinsheng
, p. 4845 - 4853 (2016)
A cost-efficient method for the preparation of a series of N-substituted 2-fluoroallylamines and their application in the synthesis of fluoroalkene-containing lactams are described. N-substituted 2-fluoroallylamine could be readily synthesized from methyl 2-fluoroacrylate via aminolysis and subsequently selective reduction of the amide group. These amines were further converted into the corresponding amides with diverse acids bearing a terminal double bond. The Ring-Closing Metathesis (RCM) of the resulting amides led to the formation fluorovinyl-containing lactams in good yields.
Substrate encapsulation: An efficient strategy for the RCM synthesis of unsaturated ε-lactones
Pentzer, Emily B.,Gadzikwa, Tendai,Nguyen, Sonbinh T.
, p. 5613 - 5615 (2008)
(Chemical Equation Presented) A facile substrate-encapsulated RCM-based synthesis of 7-membered lactones is reported. Coordination of the α,ω-dienyl ester precursor to the bulky Lewis acid (LA) aluminum tris(2,6-diphenylphenoxide) (ATPH) provides a protective extended steric pocket to the olefin moieties, thereby favoring intramolecular RCM over intermolecular ADMET oligomerization. The LA-encapsulated esters undergo ring-closure in the presence of Ru-based olefin metathesis catalysts to give previously difficult-to-access 7-membered β,γ- and γ,δ-unsaturated lactones in good yields.
Synthesis of 1,3-bridged β-lactams embedded in a macrocyclic structure
Sierra, Miguel A.,Rodríguez-Fernández, Mamen,Manche?o, María José,Casarrubios, Luis,Gómez-Gallego, Mar
, p. 9592 - 9598 (2008)
A new approach to N1-C3 bridged macrocyclic β-lactams has been developed. Orthogonal functional groups' protection combined with RCM has allowed the construction of the bicyclic systems bearing a β-lactam motif. These systems could represent a structural alternative to the actual lactamic antibiotics and may be further transformed into a broad variety of compounds.
Sulfoxide ligand metal catalyzed oxidation of olefins
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Page/Page column 127, (2019/05/09)
The enantioselective synthesis of isochroman motifs has been accomplished via Pd(II)-catalyzed allylic C—H oxidation from terminal olefin precursors. Critical to the success of this goal was the development and utilization of a novel chiral aryl sulfoxide-oxazoline (ArSOX) ligand. The allylic C—H oxidation reaction proceeds with the broadest scope and highest levels asymmetric induction reported to date (avg. 92% ee, 13 examples ≥90% ee). Additionally, C(sp3)-N fragment coupling reaction between abundant terminal olefins and N-triflyl protected aliphatic and aromatic amines via Pd(II)/sulfoxide (SOX) catalyzed intermolecular allylic C—H amination is disclosed. A range of 52 allylic amines are furnished in good yields (avg. 76%) and excellent regio- and stereoselectivity (avg. >20:1 linear:branched, >20:1 E:Z). For the first time, a variety of singly activated aromatic and aliphatic nitrogen nucleophiles, including ones with stereochemical elements, can be used in fragment coupling stiochiometries for intermolecular C—H amination reactions.
C-H to C-N Cross-Coupling of Sulfonamides with Olefins
Ma, Rulin,Christina White
supporting information, p. 3202 - 3205 (2018/03/13)
Cross-coupling of nitrogen with hydrocarbons under fragment coupling conditions stands to significantly impact chemical synthesis. Herein, we disclose a C(sp3)-N fragment coupling reaction between terminal olefins and N-triflyl protected aliphatic and aromatic amines via Pd(II)/SOX (sulfoxide-oxazoline) catalyzed intermolecular allylic C-H amination. A range of (56) allylic amines are furnished in good yields (avg. 75%) and excellent regio- and stereoselectivity (avg. >20:1 linear:branched, >20:1 E:Z). Mechanistic studies reveal that the SOX ligand framework is effective at promoting functionalization by supporting cationic π-allyl Pd.
Dehydrogenative Allylic Aminations of But-3-enoic Acid Derivatives
Diamante, Daria,Gabrieli, Sara,Benincori, Tiziana,Broggini, Gianluigi,Oble, Julie,Poli, Giovanni
supporting information, p. 3400 - 3412 (2016/09/12)
Two complementary Pd-catalyzed protocols enabling the γ-selective intermolecular allylic amination of but-3-enoic acid derivatives are reported. These transformations can be successfully achieved via either a direct Pd(II)-catalyzed protocol or by way of a one-pot Pd(II)/Pd(0)-catalyzed sequence, depending on the nature of the nitrogen nucleophile used.
Synthesis of α-chiral-β,γ-unsaturated carboxylic acid derivatives using chiral auxiliaries
Poremba, Kelsey E.,Lee, Victoria A.,Sculimbrene, Bianca R.
, p. 5463 - 5467 (2015/03/30)
We report an efficient and reliable method for the synthesis of α-chiral-β,γ-unsaturated carboxylic acid derivatives using chiral auxiliaries and vinylacetic acid. Two well-established chiral auxiliaries ((S,S)-pseudoephedrine and (R)-benzyl-oxazolidinone) were chosen to test the merits of this method. Six different electrophiles were examined in the diastereoselective alkylation with both auxiliaries. The pseudoephedrine auxiliary provided isolated yields between 61 and 85% and diastereomeric ratios all greater than 96:4. Employing the same reactions as with the pseudoephedrine derivative, the corresponding oxazolidinone auxiliary provided isolated yields between 0 and 80% with diastereomeric ratios from 80:20 to 93:7.
Platinum-catalyzed intramolecular hydrohydrazination: Evidence for alkene insertion into a Pt-n bond
Hoover, Jessica M.,Dipasquale, Antonio,Mayer, James M.,Michael, Forrest E.
supporting information; body text, p. 5043 - 5053 (2010/06/13)
Dicationic (bpy)Pt(II) complexes were found to catalyze the intramolecular hydrohydrazination of alkenes. Reaction optimization revealed Pt(bpy)Cl 2 (10 mol %) and AgOTf (20 mol %) in DMF-d7 to be an effective catalyst system for the conversion of substituted hydrazides to five- and six-membered N-amino lactams (N-amino = N-acetamido at 120 A°C, N-phthalimido at 80 A°C, -OTf = trifluoromethanesulfonate). Of the four possible regioisomeric products, only the product of 5-exo cyclization at the proximal nitrogen is formed, without reaction at the distal nitrogen or 6-endo cyclization. The resting states were found to be a 2:1 Pt-amidate complex (25, for N-acetamido) of the deprotonated hydrazide and a Pt-alkyl complex of the cyclized pyrrolidinone (20 for N-phthalimido). Both complexes are catalytically competent. Catalysis using 25 as the precatalyst shows no rate dependence on added acid (HOTf) or base (2,6-lutidine). The available mechanistic data are all consistent with a mechanism involving N-H activation of the hydrazide, followed by insertion of the alkene into the Pt-N bond, and finally protonation of the resulting cyclized alkyl complex by hydrazide to release the hydrohydrazination product and regenerate the active Pt-amidate catalyst.
Synthesis of oxazinyl analogues of fosmidomycin using RCM methodology
Van Der Jeught, Sarah,Stevens, Christian V.,Dieltiens, Nicolai
, p. 3183 - 3187 (2008/09/19)
Fosmidomycin is a promising antimalarial compound with a novel mode of action, the inhibition of 1-deoxy-D-xylulose 5-phosphate reductoisomerase, a key enzyme in the biosynthesis of isoprenoids through the nonmevalonate pathway. This paper describes the synthesis of a series of analogues in which the hydroxamate moiety is incorporated in a ring structure, leaving the complexation with the enzyme up to the oxygen lone pairs instead of the free hydroxyl group. The antimalarial activities of the different analogues are currently under investigation. Georg Thieme Verlag Stuttgart.
Ligand effects in the synthesis of N-heterocycles by intramolecular Heck reactions
Cropper, Emma L.,White, Andrew J. P.,Ford, Agnes,Hii, King Kuok
, p. 1732 - 1735 (2007/10/03)
Chemo- and regioselectivity of intramolecular Heck reactions are dependent on the type of ligand employed. Six- to eight-membered benzolactams are produced in good yields using PPh3 as ligand. In contrast, a biaryl coupling occurred preferentially under ligandless conditions to form a dihydrophenanthridine product. Conformations of the seven- and eight-membered benzolactams in the solid state were examined by X-ray crystallography.
