✦ LIBER ✦

Combined quantum chemical and MM-approach to the endo/exo selectivity of diels-alder reactions in polar media

✍ Scribed by Ingo Schlachter; Jochen Mattay; Josef Suer; Udo Höweler; Gudrun Würthwein; Ernst-Ulrich Würthwein

Publisher: Elsevier Science
Year: 1997
Tongue: French
Weight: 904 KB
Volume: 53
Category: Article
ISSN: 0040-4020
DOI: 10.1016/s0040-4020(96)00957-x

No coin nor oath required. For personal study only.

✦ Synopsis

Abstraci: The endolexo selecttviry of Diels-Alder reactions tn water and methanol is studied with semiempirical methods using the SCRF approach and a combined quantum chemical (transition state) and molecular mechanics (solvent molecules) method lQCIMA4) to determine the effect of protic solvents on the trunsition safe energies. Evidently. the number of hydrogen bonds that causes strong Coulomb interacfion. discriminafes heats offormation of transition states. The results indicate that the s-cisls-trans conformation of acrylates controls the endolexo selectivily.

📜 SIMILAR VOLUMES

Chemistry of Opium Alkaloids, XLIII – A

Chemistry of Opium Alkaloids, XLIII – A PM3 Computational Approach to the Selectivity in the Diels-Alder Reactions of Thebaine and Analogues with Methyl Propenoate

✍ Baas, Jan M. A. ;Woudenberg, Richard H. ;Maat, Leendert 📂 Article 📅 1997 🏛 John Wiley and Sons 🌐 English ⚖ 603 KB

## Abstract Geometrically fully‐optimized transition structures are calculated for the Diels‐Alder adducts of methyl propenoate and the 3‐demethoxy derivatives of the dienes thebaine, 6‐demethoxythebaine, 5β‐methylthebaine, and 5β‐methyl‐6‐demethoxythebaine using the semiempirical PM3 method. The n