Oxidative coupling with

The regioselectivity and syn stereochemistry of hydroboration-oxidation coupled with a knowledge of the chemical properties of alkenes and boranes contribute to our under standing of the reaction mechanism... 

Oxidation of thiol 287 with air in glyme gave disulfide 288, which on intramolecular oxidative coupling with A,)V-dibromoisocyanurate formed macrocycle 289 in 42% yield (Scheme 188) (99MI3). 

In a Kumada-Corriu reaction, an aryl halide is oxidatively coupled with a homogeneous nickel(ll)-phosphine catalyst [2], This species reacts with a Grignard reagent to give biaryl or alkylaryl compounds. Later, palladium-phosphine complexes were also successfully applied. By this means, stereospecific transformations were achieved. 

Methods for disposing of diisopropyl methylphosphonate include microwave decomposition, ultraviolet and infrared laser-induced photodestruction, chemical oxidation coupled with ultraviolet radiation catalyzation, and adsorption using granular activated carbon (Bailin et al. 1975 Calgon 1977 ... 

An improved synthesis of dithieno[3,2-A2, 3 -<7]thiophene 15a has been achieved from 2,3-dibromothiophene 304 (Scheme 57). Lithiation of 2,3-dibromothiophene 304 using -butyllithium followed by oxidative coupling with cupric chloride provided 3,3 -dibromo-2,2 -bithiophene 305 in 79% yield. Treatment of 305 with 2 equiv of -butyllithium in ether at —78 °C under nitrogen for 40 min and then adding benzenesulfonic acid thioanhydride and leaving the reaction mixture to reach room temperature afforded dithieno[3,2-A2, 3 -<7]thiophene 15a in 70% yield <2002TL1553>. 

Srinivasan found that the typical stoichiometric Pd(OAc)2 conditions effect cyclization of 2-(N-arylaminomethyl)indoles to aryl-fused p-carbolines in low yield [e.g., 51 to 52] [73]. Similar to the chemistry observed with N-(phenylsulfonyl)pyrrole, 1,4-naphthoquinone also undergoes Pd(OAc)2 oxidative coupling with A-(phenylsulfonyl)indole to give 53 in 68% yield [74],... 

The reduction potentials of some redox couples are given in Table 7.1. The potentials listed are written as if they are for reduction couples, with any reactions written as oxidation couples with potential values of the same magnitude but opposite sign. 

So, both effects maintain an enlarged local concentration of active catalytic centers and cause the rate of oxidative coupling with polymeric catalysts to be higher than with equivalent amounts of low molecular weight analogs, especially for low 1igand/copper ratios. This rate enhancement is clearly demonstrated in Figure 5 for polydentates (I) vs. DMBA (J 7), and was also found for polydentate (II) vs. pyridine (18). 

Scheme 9 O-protection of amino acids by oxidative coupling with phenols.

A molybdenum-mediated oxidative coupling of aniline 1 with cyclohexene 2a provides carbazole 3. Alternatively, the same overall transformation of aniline 1 to carbazole 3 is achieved by iron-mediated oxidative coupling with cyclo-hexa-1,3-diene 2b or by palladium-catalyzed oxidative coupling with arenes 2c. The use of appropriately substituted anilines and unsaturated six-membered hydrocarbons opens up the way to highly convergent organometallic syntheses of carbazole alkaloids. 

Scheme 17. Mechanism for Electrolyte Oxidation Coupled with Spinel Disproportionation and Mn + Dissolution...

The oxidative coupling with catalytic quantities of Cu salts in pyridine or other suitable amines has a wide scope. There are a few cases of less successful reactions. We obtained low yields of MejSiOCOCSiMeg from the reaction of Me3SiCfeCH with oxygen in pyridine or TMEDA in the presence of CuCl and moderate yields of MejSiO QsCCsCCT SiMej in the oxidation of MejSiCJ CsCH under similar conditions. 

Table 8.2 shows the results of the cross-coupling reaction between two differently substituted 2-naphthol derivatives using the CuCl-(5)Phbox catalyst. In conclusion, the first catalytic asymmetric oxidative coupling with a high cross-coupling selectivity was accomplished under mild conditions. 

Methyl-3-phenyl-l,2,4-thiadiazol-5-one hydrazone contains the amidrazone group necessary for oxidative coupling with suitable phenols or amines to yield azo-dyes. Thus, condensation products (288... 

Treatment of the 2-oxopyrido[l,2-a]pyrimidine (22 R = H) with tri-ethyloxonium fluoroborate and subsequently with m-nitrobenzaldehyde gave the pyrido[l,2-a]pyrimidines(200). Hydrolysis of 200 with hydrochloric acid yielded 2-hydrazono-2/f-pyrido[l,2-a]pyrimidine following oxidative coupling with 1-hydroxy-2-napthanilide or 4-acetylaminodi-phenylamine, this was utilized for the preparation of azo dyes.252... 

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