Diels–Alder reactions of trichloro-1,2,4-triazine: intramolecular additions with 1,5 and 1,6 dienes

Reactions of quadricyclane with fluorinated nitrogen-containing compounds. Synthesis of 3-aza-4-perfluoroalkyl-tricyclo[4.2.1.02,5]non-3,7-dienes

“…In minor isomer 7b the value of coupling constant H-2/H-5 is slightly higher (J 3 H-2ÀH-5 ¼ 5:7 Hz). It should be pointed out that stereoselective formation of exo-3-aza-tricyclo[4.2.1.0 2,5 ]non-7-enes was also previously reported in the reactions of fluorinated azines and 1 [7][8][9].…”

“…Despite the fact that numerous examples of [2 s + 2 s + 2 p ] cycloaddition reactions of 1 with a variety of dienophiles [2][3][4][5][6][7][8][9][10][11] have been reported, data on the reactions of 1 with nitrogen-containing compounds are limited to a few examples including cycloaddition of 1 to R-N=N-R [5,6], bis(phenylsulfonyl)-o-benzoquinondiimine [11], RN=CHP(O)(OEt) 2 [10] and several fluorinated azines [7][8][9]. Most of reported [2 + 2 + 2] reactions of 1 are quite interesting from the point of view of synthetic chemistry, since due to high stereoselectivity these reactions often result in selective formation of exo-tricyclononene derivatives, containing a four-membered fragment in exo-position relative to one carbon bridge of the norbornene system [1,[5][6][7][8][9][10][11]. In search for new monomers for preparation of functional polymers for the next generation microlithography [12,13], we started investigation of the reactivity of quadricyclane towards fluorinated substrates.…”

Synthetic Chemistry of Quadricyclane

“…Quite unusual formation of 2,3,6-trichloropyridine (50) was reported in reaction of trichloro-1, 2, 4-triazine (49) and Q [47]. The reaction proceeds through formation of dihydropyridine 51 (forming after elimination of nitrogen from initially formed intermediate cycloadduct) and followed by the conversion of 51 into 50 after loss of cyclopentadiene fragment.…”

Six‐Membered Heterocycles: Triazines, Tetrazines and Other Polyaza Systems

“…In addition, the intermolecular Diels-Alder reaction has been studied and used to obtain condensed pyrimidines, pyridines [339,370,389,390] and b-carbolines [391], tetrahydro-1,5-naphthyridines and related heterocycles [392]. Reaction of the unsubstituted 1,2,4-triazine 1-oxides 217 with benzyne gives the 1,3-benzoxazepidines 218 via 1,3-dipolar cycloadducts [393] (Scheme 20.66).…”