xxx As di-aryxxx equivalents in polycyclic axxx synthesis

Optical sensing of aqueous boron based on polymeric hydroxytriphenylene derivatives

“…21,22 In fact, preparation of asymmetrical derivatives through this single step strategy gives low yields and is very laborious due to the statistical formation of several derivatives. Alternative strategies to prepare asymmetrical HHTP derivatives 23 rely on: (i) terphenyl intermediates, prepared by oxidative coupling to form biaryl bonds from arenes, by palladium-catalyzed coupling with arylzinc halides, followed by oxidative cyclization with FeCl 3 / H 2 SO 4 , 24,25 or by photocyclization of the terphenyl units (although the later presents a problem of regioselectivity for asymmetric substitution, usually decreasing the yield); 26 (ii) biphenyl intermediates, obtained mainly by palladiumcatalyzed coupling reactions, 27 inter or intramolecular DielsAlder reactions, 28 or oxidative cyclization with FeCl 3 ; (iii) naphthyl intermediates, using Diels-Alder cicloadditions to obtain triphenylenes, 29 (which can also be obtained by classical Friedel-Cras chemistry from functionalized naphthalenes); or (iv) phenanthryl cores, where the last peripheral ring of the triphenylene is formed on an isolated phenanthrene derivative by a Diels-Alder reaction, in which the diene is frequently a phenanthrene with exocyclic double bonds.…”

A Superior Synthesis of Longitudinally Twisted Acenes

“…Refluxing 7 with tetracyclone (3)i nn itrobenzene formed 9,11,12,13,14,16-hexaphenyldibenzo[a,c]tetracene-10,15-dione (13)i n2 2% yield (Scheme 3), ar easonable precursor for the previously reported9 ,10,11,12,13,14,15,16-octaphenyldibenzo-[a,c]tetracene [28] (14). Phenyllithium was added to 13 in dry THF,b ut unlike with the previous syntheses, isolation of the crude diol was skipped-a solution of SnCl 2 and HCl were added directlyt ot he reactionc ontents, giving 14 in 40 % yield.…”

“…The synthetic methodology used to produce compounds 1 and 2,and which is predominantly used to synthesize sterically congested acenes in general, [1,[10][11][12][13][14][15] is by what we will refer to as the "benzyne" approach: the design of ab enzyne precursor and its subsequent trappingb yadiene compatiblew ith the reactionc onditions necessaryt og enerate the aryne.T ypically, this requires long syntheses resultingi nl ow overall yields. For instance, anthracene 1 has ac onvergent eight-step synthesis from commercially availabletetracyclone (3)and gave areported overall yield of 0.1 %.…”

Highly diastereoselective synthesis of a novel functionalized benzocyclotrimer

“…This reactive intermediate was captured by furan, acting as dienophile in a [4+2] cycloaddition (Scheme 1). [16][17][18][19][20][21][22][23][24][25] The resulting oxabicycle 4 was brominated according to a well-established radical-driven procedure, 14 which avoids…”