- Acid Activation in Phenyliodine Dicarboxylates: Direct Observation, Structures, and Implications
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The use of the hypervalent iodine reagents in oxidative processes has become a staple in modern organic synthesis. Frequently, the reactivity of λ3 iodanes is further enhanced by acids (Lewis or Br?nsted). The origin of such activation, however, has remained elusive. Here, we use the common combination of PhI(OAc)2 with BF3·Et2O as a model to fully explore this activation phenomenon. In addition to the spectroscopic assessment of the dynamic acid-base interaction, for the first time the putative PIDA·BF3 complex has been isolated and its structure determined by X-ray diffraction. Consequences of such activation are discussed from a structural and electronic (DFT) points of views, including the origins of the enhanced reactivity.
- Izquierdo, Susana,Essafi, Stéphanie,Del Rosal, Iker,Vidossich, Pietro,Pleixats, Roser,Vallribera, Adelina,Ujaque, Gregori,Lledós, Agustí,Shafir, Alexandr
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p. 12747 - 12750
(2016/10/13)
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- On the mechanism of nucleophilic substitution of allenyl(aryl)iodine(III): Formation of propargyl cation and competition with sigmatropic rearrangement
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The ratios of nucleophilic substitution versus [3,3] sigmatropic rearrangement for the collapse of allenyl(aryl)-iodine(III), generated from the reaction of aryliodanes with propargylsilanes in the presence of BF3- Et2O in alcohols, were determined. A proposed mechanism involves generation of propargyl cations from the allenyliodine(III) via a unimolecular pathway.
- Ochiai, Masahito,Kida, Michio,Okuyama, Tadashi
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p. 6207 - 6210
(2007/10/03)
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- Tandem radical reactions of isonitriles with 2-pyridonyl and other aryl radicals: Scope and limitations, and a first generation synthesis of (±)-camptothecin
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Photolysis of N-propargyl-6-halo-2-pyridones and related aromatic halides in the presence of aryl isonitriles provides tetra- and penta-cyclic products in a single step by a sequence of radical addition to the isonitrile followed by two cyclizations. The scope and limitations of the process are described along with a first generation synthesis of racemic camptothecin.
- Curran, Dennis P.,Liu, Hui,Josien, Hubert,Ko, Sung-Bo
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p. 11385 - 11404
(2007/10/03)
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- Generation of allenyliodinanes and their reductive iodonio-Claisen rearrangement
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Reported for the first time are the generation of allenyliodinanes and their reductive iodonio-Claisen rearrangement. Reaction of propargylsilanes, germanes, and stannanes with aryliodinanes in the presence of BF3-Et2O undergoes a re
- Ochiai, Masahito,Ito, Takao,Takaoka, Yoshikazu,Masaki, Yukio
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p. 1319 - 1323
(2007/10/02)
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