1099-45-2Relevant articles and documents
Cyclic Model for the Asymmetric Conjugate Addition of Organolithiums with Enoates
Nishimura, Katsumi,Fukuyama, Naoshi,Yamashita, Mitsuaki,Sumiyoshi, Takaaki,Yamamoto, Yasutomo,Yamada, Ken-Ichi,Tomioka, Kiyoshi
, p. 2256 - 2264 (2015)
The chiral diether ligand controlled asymmetric conjugate addition of organolithiums to nona-2,7-dienedioates preferentially proceeds via the s-cis conformation with coordination of the carbonyl oxygen atom to the lithium to give a lithium E-enolate intermediate. Subsequent intramolecular conjugate addition of the enolate also proceeds via a cyclic transition state involving the lithium and the s-cis-enoate, resulting in trans,trans-trisubstituted cyclohexanes with high enantiomeric excesses and yields.
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Suvorov et al.
, (1969)
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Catalytic Asymmetric Synthesis of Cyclopentene-spirooxindoles Bearing Vinylsilanes Capable of Further Transformations
Cobo, Angel A.,Armstrong, Brittany M.,Fettinger, James C.,Franz, Annaliese K.
, p. 8196 - 8200 (2019)
We report a scandium-catalyzed [3 + 2] annulation of alkylideneoxindoles with allenylsilanes for the enantioselective formation of cyclopentene-spirooxindoles containing vinylsilanes. Using a Sc(OTf)2/PyBOX/BArF complex, the spiroannulation of allenylsilanes affords products with >94:6 dr and >90:10 er. The effect of the counterion and ligand to control selectivity is discussed. The transformation of the vinylsilane is demonstrated using cross-coupling, epoxidation, and Tamao-Fleming oxidation reactions. A series of competition experiments provide a comparison of nucleophilicity between allyl- and allenylsilanes.
Asymmetric Catalytic Diverse Ring Opening/Cycloadditions of Cyclobutenones with (E)-Alkenyloxindoles and (E)-Dioxopyrrolidines
Luo, Yao,Zhang, Hang,Wang, Siyuan,Zhou, Yuqiao,Dong, Shunxi,Feng, Xiaoming
, p. 2645 - 2650 (2020)
Highly enantioselective ring-opening/cycloaddition reactions of cyclobutenones were achieved by employing chiral N,N′-dioxide/metal complexes as the catalysts. The Diels-Alder type cycloaddition with (E)-alkenyloxindoles yielded spirocyclohexaneoxindoles with excellent results. Meanwhile, a hetero-Diels-Alder process occurred with (E)-dioxopyrrolidines to afford spiropyrrolidinone-dihydropyranone derivatives.
Synthesis and Structure of Mixed Phosphonium-iodonium Ylide
Matveeva,Podrugina,Grishin,Tkachev,Zhdankin,Aldoshin,Zefirov
, p. 536 - 541 (2003)
A mixed phosphonium-iodonium ylide, phenyliodoniumethoxycarbonylmethylenetriphenyl-phosphorane borofluoride, was synthesized. Its structure was established by means of X-ray diffraction analysis. Temperature dependence of 1H, 13C, and 31P spectra of the ylide synthesized was investigated. A dynamic equilibrium between Z and E-isomers was observed.
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Denney,Ross
, p. 998 (1962)
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Titanium(IV)-catalyzed stereoselective synthesis of spirooxindole-1-pyrrolines
Badillo, Joseph J.,Ribeiro, Carlos J. A.,Olmstead, Marilyn M.,Franz, Annaliese K.
, p. 6270 - 6273 (2014)
A stereoselective cyclization between alkylidene oxindoles and 5-methoxyoxazoles has been developed using catalytic titanium(IV) chloride (as low as 5 mol %) to afford spiro[3,3-oxindole-1-pyrrolines] in excellent yield (up to 99%) and diastereoselectivity (up to 99:1). Using a chiral scandium(III)-indapybox/BArF complex affords enantioenriched spirooxindole-1-pyrrolines where a ligand-induced reversal of diastereoselectivity is observed. This methodology is further demonstrated for the synthesis of pyrrolines from malonate alkylidene and coumarin derivatives.
Efficient and regioselective one-pot synthesis of S-vinyl dithiocarbamates from electron-deficient allenes, amines and CS2
Li, Ridong,Leng, Penglin,Liu, Bin,Wang, Xin,Ge, Zemei,Li, Runtao
, p. 5707 - 5712 (2016)
A novel and efficient one-pot procedure for the synthesis of S-vinyl dithiocarbamates from electron-deficient allenes, amines and CS2was presented. The reactions proceed at room temperature for 10–30?min without any catalyst to afford the products in high yields, excellent regioselectivity and stereoselectivity.
Blue Light-Emitting Diode-Mediated in Situ Generation of Pyridinium and Isoquinolinium Ylides from Aryl Diazoesters: Their Application in the Synthesis of Diverse Dihydroindolizine
Guha, Souvik,Maiti, Debajit,Prabakar, Tejas,Sar, Saibal,Sen, Subhabrata
, p. 11736 - 11747 (2021/09/02)
Blue light-emitting diode-mediated environmentally sustainable three component reactions among pyridine/isoquinoline 1/2, aryl diazoesters 3, and acrylic ester/3-alkenyl oxindoles 5/6 provide various dihydroindolizines 7 to 9 in excellent yield. The principle of the strategy is photolytic generation of nitrogen ylides from N-heteroarenes and aryl diazoesters and their subsequent [3 + 2] cycloaddition reaction with dipolarophiles. Detailed mechanistic analysis of the transformation through control experiments establishes this strategy as the foundation for the photolytic multicomponent reaction.
Organocatalyzed [2+2] Cycloaddition Reactions between Quinone Imine Ketals and Allenoates
Liu, Teng,He, Chixian,Wang, Fan,Shen, Xiang,Li, Yongqin,Lang, Man,Li, Guijun,Huang, Chao,Cheng, Feixiang
, p. 518 - 526 (2020/10/12)
A new cycloaddition reaction of quinone imine ketals (QIKs), which could be utilized to the construction of functionalized azaspirocyclics under mild conditions, is described. This transformation involved a [2+2] cycloaddition reaction between QIKs and allenoates catalyzed by DABCO, and then treatment with 1 N HCl in one-pot. The strategy could provide a practical route to access azetidine-fused spirohexadienones in good to excellent yields and with high E -selectivity.
