Stereoselective Diels–Alder reactions of 3-phosphonopropenoyl derivatives of 1,3-oxazolidin-2-ones

Addition Reactions: Cycloaddition

“…95 de The Diels-Alder reactions of 3-phosphonopropenoyl derivatives of 1,3-oxazolidin-2-ones with cyclic and acyclic dienes are highly stereoselective. 96 The Diels-Alder cycloadditions of the natural cyclolignins thuriferic acid and epithuriferic acid with cyclopentadiene have been reinvestigated. In the case of thuriferic acid (86), all four possible α,β-isomers (87)(88)(89)(90) were isolated and characterized, while with epithuriferic acid only the β-isomers were isolated and identified (Scheme 23).…”

“…105 The hypervalent iodine-mediated oxidative dearomatization-Diels-Alder cascade was investigated as a means of preparing the [2.2.2]bicyclic core of the natural product tashironin. Trapping of allyl alcohols during the oxidative dearomatization of phenol (95) produced the desired five-membered acetal (96), whereas trapping of the allenyl alcohols resulted in the undesired six-membered acetal (97) (Scheme 25). 106 The configuration of the stereogenic C(3) centre bearing the protected hydroxyl group is crucial to the diastereoselectivity in the IMDA reaction de of (E,E,E)-nona-1,6,8-trienes leading to products containing the bicyclo[4.3.0]non-2-ene carbon skeleton.…”

Progress in Catalytic Asymmetric Reactions with 7-Azaindoline as the Directing Group

“…At present, the main types of directing groups are as follows: 2-oxazolidone (A) [29][30][31][32][33][34][35][36][37][38][39][40], tetrahydropyrrole 2,5-dione (B) [41][42][43], pyrazole or 3,5-dimethylpyrazole (C or D) [44][45][46][47][48][49][50][51][52][53][54][55][56], and 8-aminoquinoline (E) [57][58][59][60][61][62][63][64][65]. They coordinate with metals to form stable five-or six-membered ring complexes that control the stereoselectivity of the reaction through a specific chiral environment (Scheme 1).…”