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Novel Concepts in Directed Biaryl Synthesis, XVI. Synthesis and Structure of Benzonaphthopyrans; Helically Distorted, Bridged Biaryls with Different Steric Hindrance at the Axis
Author(s) -
Bringmann Gerhard,
Hartung Thomas,
Göbel Lothar,
Schupp Olaf,
Peters Karl,
von Schnering Hans Georg
Publication year - 1992
Publication title -
liebigs annalen der chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0170-2041
DOI - 10.1002/jlac.1992199201127
Subject(s) - steric effects , chemistry , stereochemistry , crystallography
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 the degree of steric hindrance and thus molecular distortion. NMR spectroscopy and especially X‐ray diffraction reveal the ethers 3 to be helically distorted, depending on the size of the ortho substituents R.