Premium
Competition in the Three‐Component System Triphenylphosphane/Azo Ester/3‐Hydroxy‐Carboxylic Acid: OH versus COOH‐Activation
Author(s) -
Mulzer Johann,
Brüntrup Gisela,
Chucholowski Alexander
Publication year - 1979
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.197906221
Subject(s) - chemistry , steric effects , carboxylic acid , component (thermodynamics) , competition (biology) , medicinal chemistry , polymer chemistry , organic chemistry , stereochemistry , ecology , biology , physics , thermodynamics
The question whether hydroxy carboxylic acid are activated at the OH and/or the COOH group is of considerable importance, e.g. in syntheses of macrolides and peptides. IN the system (1) (PPh 3 + azo ester)/ (2) the extent of reaction at OH and/or COOH depends upon R 1 and R 1 ; Q = ( (3) + (4) )/ (5) can be correlated almost completely with Taft's steric parameter E s .