Lewis base mediated halogenation/semipinacol rearrangement of diazo compounds: new access to α-halo-quaternary ketones.
نویسندگان
چکیده
A novel halogenation/semipinacol rearrangement of α-diazo alcohol catalyzed by Lewis base has been developed through a carbene-free mechanism. This semipinacol transposition, initiated by an electrophilic halogenation (X = Cl(+), Br(+), and I(+)) of diazo carbon event, furnished a convenient synthetic route for the efficient synthesis of α-halo-quaternary ketones under mild conditions.
منابع مشابه
Brønsted acidic ionic liquid accelerated halogenation of organic compounds with N-Halosuccinimides (NXS).
The Brønsted-acidic ionic liquid 1-methyl-3-(4-sulfobutyl)imidazolium triflate [BMIM(SO(3)H)][OTf] was demonstrated to act efficiently as solvent and catalyst for the halogenation of activated organic compounds with N-halosuccinimides (NXS) under mild conditions with short reaction times. Methyl aryl ketones were converted into α-halo and α,α-dihaloketones, depending on the quantity of NXS used...
متن کاملCarbamoyl Radical-Mediated Synthesis and Semipinacol Rearrangement of β-Lactam Diols
In an approach to the biologically important 6-azabicyclo[3.2.1]octane ring system, the scope of the tandem 4-exo-trig carbamoyl radical cyclization-dithiocarbamate group transfer reaction to ring-fused β-lactams is evaluated. β-Lactams fused to five-, six-, and seven-membered rings are prepared in good to excellent yield, and with moderate to complete control at the newly formed dithiocarbamat...
متن کاملStereocontrolled synthesis of carbocyclic compounds with a quaternary carbon atom based on SN2' alkylation of γ,δ-epoxy-α,β-unsaturated ketones.
We developed a new method for stereoselective construction of an all-carbon quaternary stereogenic center on a carbocyclic ring based on regio- and stereoselective S(N)2' alkylation reactions of γ,δ-epoxy-α,β-unsaturated cyclic ketones. Treatment of the ketones, which were readily prepared in enantiomerically pure form by means of aldol condensations between 3-ethoxy-2-cycloalkenones and α,β-ep...
متن کاملPotassium N-Iodo p-Toluenesulfonamide (TsNIK, Iodamine-T): A New Reagent for the Oxidation of Hydrazones to Diazo Compounds
A new reagent for the oxidation of hydrazones to diazo compounds is described. N-Iodo p-toluenesulfonamide (TsNIK, iodamine-T) allows the preparation of α-diazoesters, α-diazoamides, α-diazoketones and α-diazophosphonates in good yield and in high purity after a simple extractive work-up. α-Diazoesters were also obtained in high yield from the corresponding ketones through a one-pot process of ...
متن کاملDirect Csp2-H enolization: an allenoate alkylation cascade toward the assembly of multi-substituted furans.
A new disconnection toward tri- and tetrasubstituted furans has been conceptualized and demonstrated. A mild, base-mediated reaction of an allenoate pronucleophile with α-halo ketones/dicarbonyl compounds results in a Csp2-alkylation/enolization/O-vinylation sequence to ultimately afford substituted furan derivatives. The reaction offers a broad scope, provides a facile access to alkyl and aryl...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Chemical communications
دوره 50 68 شماره
صفحات -
تاریخ انتشار 2014