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Steuerung der Bildungsselektivität vielgliedriger Oligomerer durch Templat‐ und Caesium‐Effekt
Author(s) -
Vögtle Fritz,
Ley Fritz
Publication year - 1983
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19831160826
Subject(s) - chemistry , trimer , caesium , pyridine , dimer , selectivity , sodium carbonate , thioacetamide , cyclohexanol , medicinal chemistry , sodium , inorganic chemistry , organic chemistry , catalysis , biochemistry
Steering of the Selectivity of Formation of Many‐membered Oligomers by Template and Cesium Effects Cyclization of the bis(bromomethyl) compounds 1 and 2 with thioacetamide in the presence of carbonates M 2 CO 3 leads to mixtures of dimers ( 3, 4 ) and trimers ( 5, 6 ) in yields ranging from 40 to 60%. Increasing cation size in the added carbonate raises the amount of trimers 5, 6 relative to the dimers 3, 4 . In the pyridine series sodium carbonate leads to predominant formation of the trimer 6 , indicating a template effect. In the pyridine and the xylylene series the cesium effect leads to an approx. 40:60 ratio of dimer and trimer, which shows that a template effect seems not to be effective in this cesium assisted cyclization.