Aryl-alkynyl

Whereas Ullmann chemistry is limited to the coupling of aryl halides, a variety of species including aryl-, alkynyl-, alkenyl-, and alkylcopper species can be produced which are highly reactive toward other substrates. 

Syntheses and Structures of R3M (R = Alkyl, Aryl, Alkynyl) and Lewis Base Adducts 288... 

Section 14.2 describes the highly stereoselective cyclopropanation chemistry of the donor/acceptor-carbenoids (Fig. 14.1a) [16]. This section introduces the range of vinyl, aryl, alkynyl, and heteroaryl functionalities that have been used as donor groups in this chemistry. Also, chiral auxiliaries and chiral catalysts that achieve high asymmetric induction in this chemistry are described [25]. The next two sections cover chemistry that is unique to the vinylcarbenoid system, namely [3-t4] cycloaddition with dienes (Fig. 14.1b see also Section 14.3) [13] and [3-1-2] cycloaddition with vinyl... 

Akiyama et al. extended this reaction to alkynylimines for the preparation of quinoline derivatives [28]. Treatment of N-aryl(alkynyl)imines 99 with 20 mol% W (CO)5(thf) in THF at reflux followed by oxidative work-up using NMO gave 2-arylquinolines 100 in reasonable yield through electrocydization of the vinylidene intermediate (Scheme 5.31). 

Scheme 5.31 Electrocyclization of N-aryl(alkynyl)imines leading to quinoline derivatives.

Other pseudo-halides are used for carbonylation. Phenyl fluorosulfonate (484) can be carbonylated to give benzoate[337]. Aryl(aryl)iodonium salts[338], aryl(alkenyl)iodonium salts (485)[339], and aryl(alkynyl)iodonium salts (486)[340] are reactive compounds and undergo carbonylation under mild conditions (room temperature, 1 atm) to give aryl, alkenyl, and alkynyl esters. Iodoxybenzene (487) is carbonylated under mild conditions in... 

Quinone synthesis. Two laboratories12 have found that the adducts formed by addition of an aryl-, alkynyl-, or heteroaryllithium to a cyclobutenedione rearrange when heated (138-160°) to hydroquinones, which are usually isolated as the quinone after air or chemical oxidation. The rearrangement involves an interme-... 

R1 = alkyl, vinylic, aryl R2 = II +, benzylic, allylic, aryl, alkynyl, vinylic TL 29 1811 (1988)... 

RMgX (R = alkyl, ally I, aryl alkynyl, vinylic)... 

RMgX, HMPA (R = 1°, 2 alkyl aryl alkynyl vinylic)... 

R = 1° alkyl, allylic, benzylic, aryl, alkynyl, vinylic, heterocyclic TL 27 6103 (1986)... 

Indenyl)rhodium(I) complexes, preparation, 7, 184—185 Indium complexes acid halide reactions, 9, 683 in alkene and alkyne allyindations, 9, 693 alkyl, aryl, alkynyls, 3, 288 in alkynylations, 9, 720... 

R = alkenyl, aryl, allyl, benzyl, propargyl R = alkenyl, aryl, alkynyl, alkyl, benzyl, allyl The Negishi Coupling was the first reaction that allowed the preparation of unsymmetrical biaryls in good yields. The versatile nickel- or palladium-catalyzed coupling of organozinc compounds... 

R = alkyl, vinyl, aryl, alkynyl R" = allyl, vinyl, aryl... 

Figure 8.3 Schematic presentation of the mechanism for the aryl-alkynyl coupling reaction...

In addition to aryl alkynyl coupling reactions involving dihaloarenes and acetylenes or dialkynylarenes which lead to poly(arylene acetylene)s, it is worth noting that these polymers have also been obtained by the Pd(0)-catalysed heteropolycondensation of dialkoxy-substituted dibromoarenes with bis(tribu-tylstannyl)acetylenes [122]. 

Iodobenzyl 2-butynyl ethers undergo a Pd-mediated cyclisation with terminal alkynes to give lf/-[2]benzopyrans. The absence of a Cu(I) co-catalyst allows an intramolecular 6-exo-dig cyclisation to compete successfully with an intermolecular Sonogashira aryl-alkynyl coupling <02T9007>. 

Pargyline (= TV-Benzyl-jV1 methyl-2-propynylamine)] (aryl alkynyl tertiary amine) [Rilmenidine (= 2-[iV-(Dicyclopropylmethyl) amino] -oxazoline) (arylaminooxazoline) [Tetrahydro-P-carboline] ((3-carboline)... 

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