The influence of structure on the efficiency of the electrochemical C-5 oxidation of (2S, 4S)- hydroxyproline carbamate esters is presented. Optimum methoxylation was observed with (2S, 4S)-4-acetoxy-l, 2-pyrrolidine-dicarboxylic acid 2-methyl 1-(2-(trimethylsilyl) ethyl) ester (19). The corresponding C-5 methoxy derivative 20 was converted into bulgecinine (4) via a stereospecific radical homologation to incorporate the C-5 hydroxymethyl substituent. ...
[Agarkov, Anton; Greenfield, Scott J.; Ohishi, Takahiro; Collibee, Scott E.; Gilbertson, Scott R. Journal of Organic Chemistry, 2004 , vol. 69, # 23 p. 8077 - 8085]
