2-Alkenyl dioxolanylium cations, new reactive dienophiles in low temperature asymmetric Diels-Alder reactions
作者:Arnaud Haudrechy、Willy Picoul、Yves Langlois
DOI:10.1016/s0957-4166(96)00470-3
日期:1997.1
orthoesters 14–22 were prepared by an exchange reaction with orthoester 13. These compounds, after treatment with trimethylsilytriflate or tin(IV) chloride, gave rise to vinyl dioxolanylium cations which proved to be very reactive dienophiles in various Diels-Alder reactions.
Hydrogen Bonding and Alcohol Effects in Asymmetric Hypervalent Iodine Catalysis: Enantioselective Oxidative Dearomatization of Phenols
作者:Muhammet Uyanik、Takeshi Yasui、Kazuaki Ishihara
DOI:10.1002/anie.201303559
日期:2013.8.26
Iodine chooses: A conformationally flexible C2‐symmetric organoiodine(III) catalyst for the highly enantioselective catalytic oxidative dearomatization of phenols has been developed. Catalysis is controlled by intramolecular hydrogen‐bonding interactions and additional achiral alcohols.
Asymmetric dearomative spirolactonization of naphthols using λ3-iodanes under chiral phase-transfer catalysis
作者:Kevin Antien、Guillaume Viault、Laurent Pouységu、Philippe A. Peixoto、Stéphane Quideau
DOI:10.1016/j.tet.2017.04.028
日期:2017.6
The asymmetric phase-transfer catalytic effect of chiral Cinchona alkaloid-derived quaternary ammonium salts was investigated in the context of the λ3-iodane-mediated dearomative spirolactonization of naphthols. The scope and limitations of this methodology were evaluated using various substrates, which were converted into spirolactones in good yields and with enantiomeric excesses up to 58%.
Ethynyl ortho esters as precursors of propargyl cations
作者:Paul G Gassman、Subhash P Chavan
DOI:10.1016/0040-4039(88)85175-x
日期:1988.1
3,3,3-Triethoxypropyne (triethyl orthopropiolate) was added to a series of 1,3-dienes at low temperature in the presence of trimethylsilyl inflate to yield the 4π + 2π products of the formal addition of ethyl propiolate to the 1,3-dienes.
Modular Synthesis of Triazole-Based Chiral Iodoarenes for Enantioselective Spirocyclizations
作者:Christian Hempel、Caeciliea Maichle-Mössmer、Miquel A. Pericàs、Boris J. Nachtsheim
DOI:10.1002/adsc.201700246
日期:2017.9.4
A new triazole‐based C1‐symmetrical chiral iodoarene was synthesized in a highly modular route. Based on enzymatic kinetic resolution of an easily accessible propargylic alcohol both enantiomers were accessible in enantiopure form. By Huisgen‐type azide‐alkyne cycloaddtion a series of differently substituted iodoarenes was synthesized in high overall yields. Finally this novel iodoarene was successfully