Progress in the chemistry of isobenzofurans

An Obtuse‐angled Corner Unit for Fluctuating Carbon Nanohoops

“…We first prepared the corner unit in the form of bromophenylated 9,10‐epoxyanthracene. Benzyne generated from phenyl trifluoromethanesulfonate and magnesium amide [Mg(TMP) 2 ⋅2 LiCl] was adopted for the Diels–Alder reaction with bromophenylated isobenzofuran 1 to afford the corner unit 2 in a good yield (Scheme ) . The corner unit 2 was then subjected to the Ni‐mediated, Yamamoto‐type macrocyclization reaction .…”

“…Benzyne generated from phenyl trifluoromethanesulfonate and magnesium amide [Mg(TMP) 2 ·2 LiCl] [16] was adopted fort he Diels-Alder reaction with bromophenylated isobenzofuran 1 [17] to afford the corner unit 2 in ag ood yield (Scheme 1). [18,19] The corner unit 2 was then subjected to the Ni-mediated, Yamamoto-type macrocyclization reaction. [20] Although the MS spectrum of the crude product indicated the presence of 5-to 8mer macrocycles (3; m = 5-8) ( Figure S8), [21] we failed to isolate each of the macrocyclesa tt his stage.…”

“…Performing one-pot Ni-mediated macrocyclization with this corner unit, we found that the number of the participating units increased up to 7t o afford synthetic precursors for [n]CPP( n = 15, 18 and 21). The aromatization wass uccessful in providing the [15]-, [18]-and [21]CPP congeners with multiple anthracenylene panels. [12] Detailed structural investigations of the [15]CPP congener revealed the presence of fluctuating structures possessinga ni ntrinsic non-belt shape.…”

Synthesis of acetylenedicarboxylic acid esters and asymmetric Diels–Alder reactions of the bis(methyl (S)-lactyl) ester

“…The preparation of complex ADA esters is, in fact, a very difficult task and it is noteworthy that literature reports of ADA ester derivatives, other than the simple dialkyl esters, are infrequent (3). Chiral esters of ADA, except for the menthyl ester, have been neglected as dienophiles in studies of asymmetric Diels-Alder reactions and the disregard of these compounds is attributed to difficul- approach in Scheme 1 makes possible the preparation of the lactyl ADA ester lb, and a study has been undertaken of its Diels-Alder reactions with various dienes such as phenylbutadiene ( 3 , orthoquinodimethanes (0-QDMs) (6), and isobenzofurans (7). These dienes have been used extensively in organic synthesis for the construction of biaryl, aryltetralin, and naphthalene compounds.…”

The synthesis and some chemical reactions of a 5a-methyl 2H-naphtho[1,8-bc]furan

“…Every attempt at oxidation of this compound with various Cr(V1) and Ce(1V) reagents, DDQ, and NBS led to decomposition and the production of mixtures displaying aromatic signals in the 'H NMR spectra. Isobenzofurans are among the most reactive dienes known (16) and have been shown (17) to react even with cyclohexene to provide adducts in good yield. The isobenzofuran 33 (18), generated in situ with glacial acetic acid from the hydroxyphthalan 32, was reacted with 19 in refluxing carbon tetrachloride for 2h.…”