The Ireland-Claisen rearrangementa of a variety of 0-protected allylic glycolate esters are described. Vicinal diastereoselectivities ranging from 7.21 to> 201 were observed, indicating that chelation control of enolate geometry is operational in the conversion of substrates 4a-c, 6a-c, and 8a, b to the corresponding methyl 2-alkoxy-3-methyl-4-pentenoates 5a-c and 7a-c and to the sesquiterpene synthons 9a, b. Four methods were developed for the ...
