𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Inter- and intramolecular hetero Diels-Alder reactions, 52. Effect of high pressure on the kinetics and selectivity of the intramolecular hetero Diels-Alder reaction of an 1-oxa-1,3-butadiene

✍ Scribed by Buback, Michael ;Abeln, Johannes ;Hübsch, Thomas ;Ott, Christian ;Tietze, Lutz F.

Publisher
John Wiley and Sons
Year
1995
Tongue
English
Weight
288 KB
Volume
1995
Category
Article
ISSN
0947-3440

No coin nor oath required. For personal study only.

✦ Synopsis

Hetero Diels-Alder reactions, intramolecular / High-pressure reactions / Diastereoselectivity / Pyrans / 1 -Oxa-l,3-butadiens / Isoxazolones

The intramolecular hetero Diels-Alder reaction of the benzylidene-isoxazolone 3 giving the adducts 4 and 5 is studied in dichlormethane under high pressure up to 5 kbar. The kinetics is measured by on-line FT-IR spectroscopy up to 3 kbar. The cycloaddition shows a clear pressure-induced increase in diastereoselectivity. For the difference in activation volume AAV+ of the reactions affording the two diastereomers, a value of -(1.6 ? 0.2) cm3 . mol-I is obtained. The activation volume d V & is determined to be -(19.4 t 0.5) cm3 . mo1-I at 343 K.

The activation enthalpy and entropy, as derived from the overall rate coefficient k measured at 1000 bar, are (62.9 t 1.7) kJ. mol-I (at 343 K) and -(135 t 11) J . mol-' . K-'.

📜 SIMILAR VOLUMES

Inter- and intramolecular hetero diels-a
Inter- and intramolecular hetero diels-alder reactions, 40. Effect of high pressure on the stereoselectivity of intermolecular hetero diels-alder reactions
✍ Tietze, Lutz F. ;Hübsch, Thomas ;Oelze, Jens ;Ott, Christian ;Tost, Winfried ;Wö 📂 Article 📅 1992 🏛 Wiley (John Wiley & Sons) 🌐 English ⚖ 891 KB

Hetero Diels-Alder reactions / Enamino ketones 1 High-pressure reactions / Pyrans The hetero Diels-Alder reaction of enamino ketone 1 with the vinyl ethers 7-11 leading to the dihydropyrans 12a-e and 13ae is studied in dichloromethane under high pressures up to 7 kbar. The kinetics is measured by o

Inter- and intramolecular hetero Diels-A
Inter- and intramolecular hetero Diels-Alder reactions, 51. Intermolecular hetero Diels-Alder reactions of enamino ketones. Effect of high pressure on the kinetics and diastereoselectivity
✍ Tietze, Lutz F. ;Hübsch, Thomas ;Ott, Christian ;Kuchta, Gabriele ;Buback, Micha 📂 Article 📅 1995 🏛 John Wiley and Sons 🌐 English

## Abstract The hetero Diels‐Alder reaction of the enamino ketones 1b and 1c with ethyl vinyl ether (2) in dichloromethane to give the dihydropyrans 3b/4b and 3c/4c is studied at high pressure up to 5 kbar. The kinetics is measured by on‐line FT‐IR spectroscopy up to 3 kbar. The cycloadditions show

Inter- and intramolecular hetero diels-a
Inter- and intramolecular hetero diels-alder reactions, 41. Unusual stereocontrol in intramolecular hetero diels-alder reactions of 2-Aza-1,3-butadienes. A stereoselective sequential synthesis of annulated tetrahydropyridines
✍ Tietze, Lutz F. ;Utecht, Jens 📂 Article 📅 1992 🏛 Wiley (John Wiley & Sons) 🌐 English ⚖ 542 KB

Azabutadienes f Isoxazoles f Tetrahydropyridines 1 Diels-Alder reactions / Sequential transformations Condensation of aldehydes 1 ae with 5-amino-3-methylisoxazole (4) gives the corresponding imines 5a-e with a 2-aza-1,3-butadiene moiety, which cyclize selctively, e.g. 5a to form the trans-fused tet