Asymmetric Total Synthesis of the Iridoid β-Glucoside (+)-Geniposide via Phosphine Organocatalysis

2009-04-16T00:00:00Z (GMT) by Regan A. Jones Michael J. Krische
Phosphine-catalyzed [3 + 2] cycloaddition of ethyl-2,3-butadienoate with enone (<i>S</i>)-<b>3b</b> occurs with high levels of regio- and stereocontrol to deliver the <i>cis</i>-fused cyclopenta[c]pyran <b>4</b> characteristic of the iridoid family of natural products. Cycloadduct <b>4</b> was converted to the iridoid glycoside (+)-geniposide in 10 steps.