Concept

Superbase

Related publications (21)

Switchable reactivity: the site-selective functionalization of trifluoromethyl-substituted pyrazoles

Modern organometallic methods enable the regioflexible conversion of simple heterocyclic starting materials into families of isomers and congeners. Depending on the choice of the reagent, 1-methyl-5-(trifluoromethyl)pyrazole undergoes deprotonation and sub ...

2002

1,2-Didehydro-3- and -4-(trifluoromethoxy)benzene: the "aryne" route to 1- and 2-(trifluoromethoxy)naphthalenes

Upon treatment of 1-bromo-2-(trifluoromethoxy)benzene with lithium diisopropylamide (LDA) at -100 DegC, 3-bromo-2-(trifluoromethoxy)phenyllithium is generated. It can be trapped as such, but isomerizes to afford 2-bromo-6-(trifluoromethoxy)phenyllithium wh ...

2001

Halogen shuffling in pyridines: site selective electrophilic substitutions of 2-chloro-6-(trifluoromethyl)pyridine

Fabrice Cottet

When treated with lithium diisopropylamide in THF at -85 Deg and subsequently with iodine, 2-chloro-6-(trifluoromethyl)pyridine is neatly converted into its 3-iodo deriv. The latter can be quant. isomerized to afford 2-chloro-4-iodo-6-(trifluoromethyl)pyri ...

1998

Regioselective ortho-lithiation of chloro- and bromo-substituted fluoroarenes

Deprotonation of fluoroarenes carrying chlorine or bromine as addnl. substituents occurred always at a position adjacent to a fluorine if accomplished with potassium tert-butoxide activated butyllithium or lithium 2,2,6,6-tetramethylpiperidide. For example ...

1996

Superbases as powerful tools in organic syntheses

A review with 136 refs. on the use of organometallic and other superbases in org. synthesis. [on SciFinder (R)] ...

1992

The preparation of pure allyl- and benzyl-type organoalkali intermediates via organotin compounds

Superbase metalation of alkenes or alkylbenzenes and subsequent condensation with trialkylstannyl chloride affords allyl- or benzyl-type organotin compds. that can be isolated in pure form. Treatment with sol. reagents such as methyllithium, trimethylsilyl ...

1991

A one-pot synthesis of ibuprofen involving three consecutive steps of superbase metalation

A one-pot reaction sequence consisting of three consecutive metalation and electrophilic substitution stages starting with p-xylene leads to 2-(4-isobutylphenyl)propanoic acid with a 52% overall yield. A crucial step is the alkylation of deprotonated p-eth ...

1991

Facile isomerization of oxiranes to allyl alcohols by mixed metal bases

The mixt. of LiN(CHMe2)2 and KOCMe3 (LIDAKOR reagent) promotes smooth ring opening of oxiranes to afford allyl alcs. with good to excellent yields. Internal epoxyalkanes and large-sized epoxycycloalkanes give preferentially or exclusively (E)-alkenols. The ...

1990

1,2-elimination of alcohol from homoallyl ethers under the influence of mixed metal bases

Lithium diisopropylamide in the presence of catalytic amts. of potassium tert-butoxide smoothly converts homoallyl or homobenzyl type ethers to dienes or styrenes. g,d-Unsatd. acetals give 1,3-dienyl ethers and 4-alkylidenetetrahydropyrans or dihydropyrans ...

1990

Mixed metal bases as promoters of 1,4-eliminations

When treated with the LIDAKOR mixt., allyl type ethers very readily undergo 1,4-elimination to afford conjugated dienes (E)-H2C:CHCH:CH(CH2)4Me, H2C:C(:CH2)CH2CH2CH:CMe2, H2C:CHCH:CHOMe. In typical cases, the reaction is brought about stereo- and regiosele ...

1990

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