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2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (or DDQ) is the chemical reagent with formula C 6 Cl 2 (CN) 2 O 2. This oxidant is useful for the dehydrogenation of alcohols, [3] phenols, [4] and steroid ketones. [5] DDQ decomposes in water, but is stable in aqueous mineral acid. [6]
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For example, (C 6 H 5)(CH 3) 2 C + is referred to as a "benzylic" carbocation. The benzyl free radical has the formula C 6 H 5 CH 2 •. The benzyl cation or phenylcarbenium ion is the carbocation with formula C 6 H 5 CH + 2; the benzyl anion or phenylmethanide ion is the carbanion with the formula C 6 H 5 CH − 2.
(1) Fmoc-protected amino group, (2) benzyl ester protected carboxyl group and (3) tert-butyl ether protected phenolic hydroxyl group of Tyrosine. Orthogonal protection is a strategy allowing the specific deprotection of one protective group in a multiply-protected structure.
The unsubstituted compound can be prepared by oxidation of 2,2'-dipyrrolemethane with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) at −78 °C in dry dichloromethane solution. [1] An alternative synthesis that avoids the oxidation step is the condensation of 2-formyl pyrrole and pyrrole catalyzed by trifluoroacetic acid , followed by ...
This structure is typical for four-coordinate 18 e − complexes. [2] The corresponding complexes Ni(PPh 3 ) 4 and Pt(PPh 3 ) 4 are also well known. Such complexes reversibly dissociate PPh 3 ligands in solution, so reactions attributed to Pd(PPh 3 ) 4 often in fact arise from Pd(PPh 3 ) 3 or even Pd(PPh 3 ) 2 .
Chloranil is produced by chlorination of phenol to give hexachlorocyclohexa-2,5-dien-1-one ("hexachlorophenol"). Hydrolysis of the dichloromethylene group in this dienone gives chloranil: [3] C 6 H 5 OH + 6 Cl 2 → C 6 Cl 6 O + 6 HCl C 6 Cl 6 O + H 2 O → C 6 Cl 4 O 2 + 2 HCl. Chloroanil serves as a hydrogen acceptor. It is more electrophilic ...