- Asymmetric syntheses and applications of planar chiral hypervalent iodine(V) reagents with crown ether backbones
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Novel optically active hypervalent iodine(V) reagents with planar chiral crown ether backbones were synthesized using the intramolecular Huisgen reaction as a key step and L-methyl lactate as the source of chirality. The relative configurations of these r
- Yoshida, Yasushi,Kanashima, Yuto,Mino, Takashi,Sakamoto, Masami
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- 4,5-Dimethyl-2-Iodoxybenzenesulfonic Acid Catalyzed Site-Selective Oxidation of 2-Substituted Phenols to 1,2-Quinols
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A site-selective hydroxylative dearomatization of 2-substituted phenols to either 1,2-benzoquinols or their cyclodimers, catalyzed by 4,5-dimethyl-2-iodoxybenzenesulfonic acid with Oxone, has been developed. Natural products such as biscarvacrol and lacinilene C methyl ether could be synthesized efficiently under mild reaction conditions. Furthermore, both the reaction rate and site selectivity could be further improved by the introduction of a trialkylsilylmethyl substituent at the 2-position of phenols. The corresponding 1,2-quinols could be transformed into various useful structural motifs by [4+2] cycloaddition cascade reactions.
- Uyanik, Muhammet,Mutsuga, Tatsuya,Ishihara, Kazuaki
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supporting information
p. 3956 - 3960
(2017/03/27)
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- Asymmetric hydroxylative phenol dearomatization promoted by chiral binaphthylic and biphenylic iodanes
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The long-standing quest for chiral hypervalent organoiodine compounds (i.e., iodanes) as metal-free reagents for asymmetric synthesis continues. Although remarkable progress has recently been made in organoiodine-catalyzed reactions using a terminal oxidant in stoichiometric amounts, there is still a significant need for "flaskable" chiral iodane reagents. Herein, we describe the synthesis of new iodobinaphthyls and iodobiphenyls, their successful and selective DMDO-mediated oxidation into either λ3- or λ5-iodanes, and the evaluation of their capacity to promote asymmetric hydroxylative phenol dearomatization (HPD) reactions. Most notably, a C2-symmetrical biphenylic λ5-iodane promoted the HPD-induced conversion of the monoterpene thymol into the corresponding ortho-quinol-based [4+2] cyclodimer (i.e., bis(thymol)) with enantiomeric excesses of up to 94 %.
- Bosset, Cyril,Coffinier, Romain,Peixoto, Philippe A.,El Assal, Mourad,Pouysegu, Laurent,Quideau, Stephane,Miqueu, Karinne,Sotiropoulos, Jean-Marc
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supporting information
p. 9860 - 9864,5
(2014/10/15)
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- Regio- and stereoselectivities in Diels-Alder cyclodimerizations of orthoquinonoid cyclohexa-2,4-dienones
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The [4+2] cyclodimerization of cyclohexa-2,4-dienone derivatives of the orthoquinone monoketal and orthoquinol types has been the topic of numerous investigations over the last 50 years in the aim of rationalizing the extraordinary level of regio-, site-,
- Gagnepain, Julien,Méreau, Rapha?l,Dejugnac, Delphine,Léger, Jean-Michel,Castet, Frédéric,Deffieux, Denis,Pouységu, Laurent,Quideau, Stéphane
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p. 6493 - 6505
(2008/02/08)
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- Efficient access to orthoquinols and their [4 + 2] cyclodimers via SIBX-mediated hydroxylative phenol dearomatization
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(Chemical Equation Presented) SIBX, the nonexplosive formulation of the λ5-iodane 2-iodoxybenzioc acid (IBX), safely and efficiently mediates the hydroxylative dearomatization of various 2-alkylphenols and napthols into orthoquinols or their [4 + 2] cyclodimers. Reactions are typically run at room temperature using SIBX as a suspension in THF. Using these conditions, natural products such as the cyclodimer of the terpene carvacrol and, for the first time, the shikimate-derived (±)-grandifloracin were prepared in one step from their respective phenolic precursor.
- Lebrasseur, Nathalie,Gagnepain, Julien,Ozanne-Beaudenon, Aurelie,Leger, Jean-Michel,Quideau, Stephane
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p. 6280 - 6283
(2008/02/10)
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- The Synthesis of 3,10-Dihydroxydielmentha-5,11-diene-4,9-dione
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A synthesis is reported for the title compound.
- Carman, Raymond M.,Owsia, Soraya,Dongen, Jacobus M. A. M. Van
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p. 333 - 340
(2007/10/02)
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