1-aryl-5-chloro

Linear dependencies of k0bS on [ROH] are also rare for the aryl(chloro)carb-enes 200 and 201 91 hence the ranking of these carbenes is somewhat uncertain. The aryl(oxy)carbenes 203, 154a, and 154c are clearly superior to their alkyl(oxy) counterparts (198, 199) as proton acceptors.76,77 The 4-OMe... 

Diethyl aryl(chloro)methylenemalonates (1670) were reacted with aniline in the presence of triethylamine at 90°C for 12 hr to give aryl(phenyl-amino)methylenemalonates (1671) in 57-66% yields (90JOC2513). The thermal cyclization of compound 1671 (Ar = 3-furyl) at 250°C gave quinoli-necarboxylate (1672) in 85% yield. The cyclizations of compounds 1671 (Pr = Ph, 3-thienyl) in polyphosphoric acid at 210-230°C for 5 min afforded tetracyclic derivatives (1673) in 50-75% yields. 

The first example Is for the alkyl and aryl chloro alcohols. 

Figure 2. Alkyl Chloro Alcohols ( ) and Aryl Chloro Alcohols (A). Group a A6, 15, 18 group b A4, 14, 16 group c A12, 17 group d A10, 19.

Figure 4. Alkyl Chloro ( ) and Aryl Chloro (A) Compounds.

Thermolysis of aryl chloro diazirine (18) in the presence of acetone and a trapping agent such as A -phenylmaleimide gave rise to cycloadducts such as 41. The unstable adduct hydrolyzed during purification resulting in synthesis of bicyclic hemiacetals 42 and 43 as a mixture of endo and exo adducts in 37 and 8% yield, respectively. The exclusive generation of the singlet carbene was confirmed by low-temperature electron spin resonance (ESR) study of the irradiated diazirine. 

Catalyst of the Cyanation Reaction. The reaction was studied in the presence of Ni(0) complexes or aryl(chloro)nickel complexes. For a clearer interpretation the corresponding results are considered separately. A variant of the process consisting in the use of acetone cyanohydrin as source of cyanide ions is also reported. 

Very interestingly, if equimolar amounts of alkali metal are used for the reduction of the aryl(chloro)stannylene, radical anions (which will be discussed later) are formed. 

Multiple arylations of polybromobenzenes have been conducted to generate electron-rich arylamines. Tribromotriphenylamine and 1,3,5-tribromobenzene all react cleanly with A-aryl piperazines using either P(o-tolyl)3 or BINAP-ligated catalysts to form hexamine products [107]. Reactions of other polyhalogenated arenes have also been reported [108]. Competition between aryl bromides and iodides or aryl bromides and chlorides has been investigated for the formation of aryl ethers [109], and presumably similar selectivity is observed for the amination. In this case bro-mo, chloroarenes reacted preferentially at the aryl bromide position. This selectivity results from the faster oxidative addition of aryl bromides and is a common selectivity observed in cross-coupling. Sowa showed complete selectivity for amination of the aryl chloro, bromo, or iodo over aryl-fluoro linkages [110]. This chemistry produces fluoroanilines, whereas the uncatalyzed chemistry typically leads to substitution for fluoride. 

Aryl tellurium chlorides, generated from diaryl ditelluriums and chlorine and used in situ, reacted with A.iV-dichloroarenesulfonamides. Aryl tellurium trichlorides and aryl (chloro)tellurium arenesulfonimides were obtained9. 

Aryl(chloro) silanes, upon pretreatment with KF, smoothly undergo the palladium-catalyzed coupling with aryl bromides and iodides to give various biaryls. For this procedure, Pd(OAc)2 (0.5 mol%)/P(o-tol)3 (0.5 mol%) is convenient (Eq. 20). 

Much better results can be obtained with substituted aromatics. The reaction of aryl chloro- or fluoroformates which have alkyl groups in position 2 and 6 gives fluoroaromalic compounds in good yield. The Friedel-Crafts reaction is widely suppressed although Lewis acids or hydrogen fluoride are present in the reaction mixture. Another advantage of this process is that the fluoroaromalic compounds can be obtained from the fluoro- as well as from the chloroformates. which, in general, are easier to prepare, A typical example is the formation of 2-fluoro-1.3-dimethylbenzene (2). ... 

Summary Bis(trimethylsilyl)mercury cleanly reacts at low temperature with chloroiminium chlorides to form stable metal-free cyclic and acyclic diaminocarbenes as well as aryl-, oxy-, chloro-, hydrogeno- and alkyl-amino carbenes. The aryl-, chloro-and hydrogeno-amino carbenes were formed as transient intermediates that undergo dimeri2ation into the corresponding alkenes, which were isolated in good yields. Alkyl-and oxy-amino carbenes were observed at low temperature by C NMR spectroscopy. 

With the synthesis of amino oxy carbenes, we could also verify the applicability of the new method, and show that the mercury method might be an alternative to traditional ways for preparing stable amino carbenes. Aryl-, chloro- and hydrogeno-amino carbenes were formed as transient intermediates in our experiments and underwent dimerization. The dimers were generally obtained in good yields. 

Bis(a-chloroarylidene)hydrazines or 1,2-diaryl-1,2-dichloroethenes [a formal dimer of aryl(chloro)carbene] were sometimes observed as side products when 3-aryl-3-chloro-3/7-di-azirines were decomposed in alkenes. 

Denmark et al. have found that in the presence of excess TBAF the Pd-catalyzed coupling of vinylsilacyclobutanes with aryl iodides and vinyl halides proceeds efficiently and highly stereospecifically at room temperature (Scheme 10.209) [543]. Although aryl(methyl)silacyclobutanes are insensitive to aryl and vinyl hahdes under a variety of conditions, aryl(chloro)silacyclobutanes have enough reactivity for coupling with aryl iodides [544]. In this biaryl couphng the use of t-BusP serves to suppress the formation of homo-couphng products. 

R1 = alkyl, aryl, amino, alkylsulfanyl, arylsulfanyl R2 = aryl, chloro, alkylsulfanyl, arylsulfanyl NR32 = i-Pr2N, i-Bu2N... 

A -aryl-5 -chloroisothiocarbamoyl chlorides (42) in this synthesis yields 5-arylimino-3,4-diaryl-A2-l,2,4-thiadiazolines (43) [i.e. analogues of (41)] exclusively. The divergent course of the reactions is ascribed to the different reactivities of the chlorine atoms of the A -acyl- (38) and A -aryl- -chloro-isothiocarbamoyl chlorides (42) it is probable that the initial nucleophilic attack of the bases occurs at the imido-carbon of the former (38) but at the sulphenyhsulphur of the latter (42). ... 

Table 8.25 Vibrational Normal Modes of the Aryl Chloro Group ...

Mamedov VA, Saifina DF, Gubaidulhn AT, Saifina AF, Rizvanov IKh, Ganieva VR (2009b) A novel rearrangement in the system 3-[aryl(chloro)methyl]quinoxalin-2(17/)-one-a-picoline as a simple and efficient route to indolizin-2-ylbenzimidazoles. Russ Chem BuU, Int Ed 58 (9) 1986-1990. doi 10.1007/sl 1172-009-0271-4... 

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