Direct α-Oxytosylation of Carbonyl Compounds: One-Pot Synthesis of Heterocycles
摘要:
N-Methyl-O-tosylhydroxylamine is an effective reagent for the direct alpha-oxytosylation of carbonyl compounds. The reactions proceed smoothly at room temperature in the presence of both moisture and air and functional group tolerance in the substrate is good. With nonsymmetrical substrates regioselectivity for primary over secondary centers is observed and complete regiospecificity for primary over tertiary centers is obtained. Addition of a bis-heteronucleophile directly to the crude reaction mixture in a one-pot process leads to the corresponding heterocyclic product.
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‐Heterocycle‐Substituted Iodoarenes (NHIAs) to Efficient Organocatalysts in Iodine(I/III)‐Mediated Oxidative Transformations
作者:Andreas Boelke、Boris J. Nachtsheim
DOI:10.1002/adsc.201901356
日期:2020.1.7
The reactivity of ortho‐functionalized N‐heterocycle‐substituted iodoarenes (NHIAs) as organocatalysts in iodine(I/III)‐mediated oxidations was systematically investigated in the α‐tosyloxylation of ketones as the model reaction. During a systematic catalyst evolution, it was found that NH‐triazoles and benzoxazoles have the most significant positive influence on the reactivity of the central iodine
PhI- and polymer-supported PhI-catalyzed oxidative conversion of ketones and alcohols to α-tosyloxyketones with m-chloroperbenzoic acid and p-toluenesulfonic acid
作者:Yukiharu Yamamoto、Yuhta Kawano、Patrick H. Toy、Hideo Togo
DOI:10.1016/j.tet.2007.03.091
日期:2007.5
Various ketones were converted to the corresponding α-tosyloxyketones with mCPBA and p-toluenesulfonic acid in the presence of a catalytic amount of iodobenzene. Moreover, secondary alcohols were directly converted to the corresponding α-tosyloxyketones using mCPBA and catalytic amounts of iodobenzene and potassium bromide, followed by treatment with p-toluenesulfonic acid in a one-pot manner. Poly(4-iodostyrene)
Efficient Conversion of Ketones to α-Tosyloxyketones with <i>m</i>-Chloroperbenzoic Acid and <i>p</i>-Toluenesulfonic Acid in the Presence of Catalytic Amount of IL-Supported PhI in [emim]OTs
作者:Hideo Togo、Junnosuke Akiike、Yukiharu Yamamoto
DOI:10.1055/s-2007-984914
日期:——
Various ketones were smoothly converted into the corresponding α-tosyloxyketones with MCPBA and p-toluenesulfonic acid in the presence of a catalytic amount of ionic-liquid (IL)-supported PhI in room temperature ionic liquid, [emim]OTs. Moreover, the present ionic-liquid reaction media containing a catalytic amount of IL-supported PhI could be reused for the same α-tosyloxylation of ketones and thiazoles directly, keeping good yields.
A concise, simple two-step method for the preparation of [4+3] cycloadducts from ketones using Koser"s reagent and trifluoroethanol-triethylamine has been developed. This sequence affords yields similar to those obtained using the α-halo and α-mesyloxyketones, but with the advantages of simplicity in preparation and stability of the intermediates.
Ultrasound promoted hypervalent iodine reactions: (α-tosyloxylation of ketones with [hydroxy(tosyloxy)iodo]benzene
作者:Atilla Tuncay、John A. Dustman、George Fisher、Crystal I. Tuncay、Kenneth S. Suslick
DOI:10.1016/0040-4039(93)88006-5
日期:1992.12
the rates of α-tosyloxylation of ketones with [hydroxy(tosyloxy)iodo] benzene and thus provides a direct, quick, and mild method of tosyloxylation of ketones without the generation of time-consuming intermediates such as trimethylsilyl enol ether derivatives and α-hydroxy ketones. The present method also provides convenient access to the tosylates of alicyclic ketones such as cyclopentanone and cycloheptanone