The sodium salts of allyldimethylsilanol and 2-butenyldimethylsilanol undergo palladium-catalyzed cross-coupling with a wide variety of aryl bromides to afford allylated and crotylated arenes. The coupling of both silanolates required extensive optimization to deliver the expected products in high yields. The reaction of the allyldimethylsilanolate takes place at 85 °C in 1,2-dimethoxyethane with allylpalladium chloride dimer (2.5 mol %) to afford 73−95% yields of the allylation products. Both electron-rich and sterically hindered bromides reacted smoothly, whereas electron-poor bromides cross-coupled in poor yield because of a secondary isomerization to the 1-propenyl isomer (and subsequent polymerization). The 2-butenyldimethylsilanolate (E/Z, 80:20) required additional optimization to maximize the formation of the branched (γ-substitution) product. A remarkable influence of added alkenes (dibenzylideneacetone and norbornadiene) led to good selectivities for electron-rich and electron-poor bromides in 4...

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Cross-coupling of aromatic bromides with allylic silanolate salts.

Rhodium-catalyzed ortho acylation of aromatic carboxylic acids.

Cross-Coupling Reactions of Aryldiazonium Salts with Allylsilanes under Merged Gold/Visible-Light Photoredox Catalysis

Isolation and X-ray crystal structure of the cuprate complex [Li2Cu3Ph6]2-[Li4Cl2(Et2O)10]: the first X-ray structural characterization of an anionic organocopper-lithium cluster

Herein we describe a general three-step synthesis of 4-substituted chlorophthalazines in good overall yields. In the key step, N,N-dimethylaminophthalimide (8a) directs the selective monoaddition of alkyl, aryl, and heteroaryl organometallic reagents to afford 3-substituted 3-hydroxyisoindolinones 9b, 9i–9am. Many of these hydroxyisoindolinones are converted to chlorophthalazines 1b–1v via reaction with hydrazine, followed by chlorination with POCl3. We have also discovered two novel transformations of 3-vinyl- and 3-alkynyl-3-hydroxyisoindolinones. Addition of vinyl organometallic reagents to N,N-dimethylaminophthalimide (8a) provided dihydrobenzoazepinediones 15a–15c via the proposed ring expansion of 3-vinyl-3-hydroxyisoindolinone intermediates. 3-Alkynyl-3-hydroxyisoindolinones react with hydrazine and substituted hydrazines to afford 2-pyrazolyl benzoic acids 16a–16d and 2-pyrazolyl benzohydrazides 17a–17g rather than the expected alkynyl phthalazinones.

Synthesis of 4-Substituted Chlorophthalazines, Dihydrobenzoazepinediones, 2-Pyrazolylbenzoic Acid, and 2-Pyrazolylbenzohydrazide via 3-Substituted 3-Hydroxyisoindolin-1-ones

The reaction of the phenyl-copper-magnesium reagent, prepared from 2 PhMgBr and CuI, with some organic halides

The reaction of arylcoppermagnesium and other organometallic reagents with phthalic anhydride

1H and 13C NMR spectra of phenylcoppermagnesium and methylcoppermagnesium reagents

The reagent prepared from 2 PhMgBr and CuI reacts with allyl and benzyl bromides to give allylbenzene and diphenylmethane, respectively, in 52 and 62% yields. The yields rise to 82–84% in the presence of nitrobenzene as an oxidant. During the reaction with allyl bromide some copper-bromine exchange takes place. Methyl iodide reacts with the copper reagent to give toluene in 65% yield. Iodoarenes react slowly and give poorer yields of the biaryls (18–46%); in these reactions some metal-iodine exchange is observed. Nitrobenzene seems to be better as an oxidant than copper(II) chloride, which brings about some metal-chlorine exchange in addition to acting as an oxidant.

Syeda K. Nahar

Papers

The reaction of the phenyl-copper-magnesium reagent, prepared from 2 PhMgBr and CuI, with some organic halides

The reaction of arylcoppermagnesium and other organometallic reagents with phthalic anhydride

1H and 13C NMR spectra of phenylcoppermagnesium and methylcoppermagnesium reagents

The Reaction of the Phenyl-Copper-Magnesium Reagent, Prepared from 2 PhMgBr and CuI, with Some Organic Halides.