204512-01-6Relevant academic research and scientific papers
Enantioselective synthesis of protected isotetronic acids
Enders, Dieter,Dyker, Hubert,Leusink, Frederik R.
, p. 311 - 320 (2007/10/03)
Isotetronic acids are subunits of a number of natural products. They are of interest in agricultural and pharmaceutical research and are important synthetic intermediates. This paper describes the first highly diastereo- and enantioselective synthesis of isotetronic acids in 4 to 5 steps (de, ee > 98%). Key steps in the reaction sequence are the diastereoselective aldol reaction of the 2-oxoesters 5 as their SAEP hydrazones (S)-6 with aldehydes, followed by base-promoted lactonization to the hydrazonolactones 8. Subsequent oxidative cleavage of the hydrazone moiety afforded the enantiomerically pure O-protected isotetronic acids (R)-/(S)-9.
