𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Novel Concepts in Directed Biaryl Synthesis, XXXVIII. Synthesis and Structure of a Protected Lactolate-Bridged Biaryl with Relevance to the Atropisomer-Selective Ring Opening of Biaryl Lactones

✍ Scribed by Bringmann, Gerhard ;Schöner, Bernd ;Peters, Karl ;Peters, Eva-Maria ;von Schnering, Hans Georg

Publisher
John Wiley and Sons
Year
1994
Tongue
English
Weight
544 KB
Volume
1994
Category
Article
ISSN
0947-3440

No coin nor oath required. For personal study only.

✦ Synopsis

Abstract

The preparation and crystal structure of the O‐methyl‐protected analog 5 of a lactolate‐type intermediate 3 in the atropisomer‐selective ring opening of configuratively unstable lactone‐bridged biaryls 1 is described. Thus, 5a could be prepared by oxidation of the cyclic ether 7a to give the substituted pyrylium salt 6a and subsequent reaction with methanolate. Attempts to similarly prepare the more strained higher homologous 5, i.e. with a higher steric hindrance next to the biaryl axis, failed. Structural information on 5a could be obtained through X‐ray crystallography, but no decoalescence was observed in the low‐temperature NMR spectrum. magnified image

📜 SIMILAR VOLUMES

Novel concepts in directed biaryl synthe
Novel concepts in directed biaryl synthesis, XXXVII. Synthesis and enantiomerization of a nonracemic 2-hydroxy-2′-biarylcarbaldehyde, a probable intermediate in the atropo-enantioselective ring opening of biaryl lactones
✍ Bringmann, Gerhard ;Hartung, Thomas 📂 Article 📅 1994 🏛 John Wiley and Sons 🌐 English ⚖ 401 KB

## Abstract The directed preparation of a “free”, i.e. nonprotected biaryl with a phenolic OH function and a formyl group in opposite __ortho__ positions, in a nonracemic form, is described. The free activation barrier ΔG^≠^ for the atropisomerization, which was determined to be 99.2 kJ mol^−1^, is

Novel Concepts in Directed Biaryl Synthe
Novel Concepts in Directed Biaryl Synthesis, XVI. Synthesis and Structure of Benzonaphthopyrans; Helically Distorted, Bridged Biaryls with Different Steric Hindrance at the Axis
✍ Bringmann, Gerhard ;Hartung, Thomas ;Göbel, Lothar ;Schupp, Olaf ;Peters, Karl ; 📂 Article 📅 1992 🏛 John Wiley and Sons 🌐 English ⚖ 659 KB

## Abstract A simple two‐step synthesis of a series of ether‐type bridged biaryls 3, as favorable models for studies of helimerization processes, is described. Starting from the known corresponding lactones 1, a variety of differently substituted representatives 3 is prepared, greatly varying by th