Spirolaxine methyl ether

The hydroalkoxylation of an internal alkyne to afford a spiroacetal was first described by Utimoto in 1983 [85]. Using PdCl2 or PdCl2(PhCN)2 as catalyst, the spiroacetals 158 were obtained in high yield (Scheme 39). The method was not adopted as a general tool for the synthesis of spiroacetals for some time, with only a few reports exploiting the approach [86, 87]. Recent applications of palladium-catalyzed intramolecular alkyne hydroalkoxylation include syntheses of spirolaxine methyl ether [88] and enantiomers of the natural cephalosporoUdes [89]. 

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