Application of Furan as a Diene: Preparation of Condensed 1,3‐Oxazines by Retro‐Diels−Alder Reactions

Abstract

(Di-exo-3-amino-7-oxabicyclo[2.2.1]hept-5-en-2-yl)methanol (3) was treated with oxo carboxylic acids [p-toluoylpropionic acid, cis-or trans-(p-toluoyl)cyclohexanecarboxylic acid, -benzoic acid or methanobenzocyclooctenecarboxylic acid] to furnish the oxanorbornene-fused pyrrolo [1,3]oxazine 4, the isoindolo[1,3]oxazines 5 and 6, and the methanobenzocyclooctenepyrrolo [1,3]oxazine 10, together with the retroDiels−Alder products pyrrolooxazinone 7, oxazinoisoindo-

Retro‐Diels–Alder Reactions of Masked Cyclopentadienones Catalyzed by Heterogeneous Brønsted Acids

“…For example, Stµyer et al constructed Diels-Alder adducts based on furan instead of cyclopentadiene with the expectation of subsequent easier removal of the diene. [9] As is the case for the Diels-Alder cycloaddition, electron-withdrawing substituents on the dienophile component accelerate the cycloreversion, as confirmed by Czarnik et al in an investigation of the cycloreversion of cycloadducts of anthracene. [10] There are also reports of fast retro-Diels-Alder reactions of alcoholates, [11] although the major drawback of this technique is the potential for rapid racemization due to the basic conditions in which these cycloreversions proceed.…”

Chemistry of Norbornane/ene and Heteronorbornane/ene β-Amino Acids

“…26 (X = CH 2 ) can also be prepared in an exo-selective Diels-Alder reaction by photolysis at 300 nm in dry EtOH, in the presence of Et 3 N [38]. With furan 23 as diene, amidation of anhydride 26 (X = O), followed by a modified Hofmann degradation with hypochlorite, results in 3-exo-amino-7-oxabicyclo[2.2.1]hept-5-ene-2-exo-carboxylic acid (27) [39], while from cyclopentadiene 22 the 3-endo-aminobicyclo[2.2.1]hept-5-ene-2-endo-carboxylic acid (28) is obtained.…”

Advanced Methods for the Synthesis of 3-Substituted 1H-Isoindol-1-Ones

“…Cyclization of cis-2-aroyl-1-cyclohexanecarboxylic acid (53) with α,ω-alicyclic and aromatic diamines to condensed partially saturated isoindolones 54 was accompained by The condensation of aromatic or cylohexane γoxocarboxylic acids with aminoalcohols or cyclic diamines led to a variety of isomeric polycyclic isoindole-fused heterocycles containing 3 to 7 chiral carbon centres: isoindolo [ [40][41][42][43][44][45][46][47][48]. From norbornane or oxanorbornane derivatives, the methylene-bridged analogues were also prepared [49][50][51][52][53][54][55][56].…”