Mild and Efficient Desymmetrization of Diynes via Hydroamination: Application to the Synthesis of (±)-Monomorine I

An efficient silver-catalyzed desymmetrization of amino diynes via hydroamination is reported. A variety of functionalized I-pyrroline derivatives were synthesized in 73% to 88% isolated yields (>98% by H-1 NMR in some cases). The usefulness of this mild hydroamination method was further shown by the desymmetrization of unprotected tert-hydroxy diynes. Structures of two transition states have been studied computationally. An application of this method was demonstrated by a short and efficient synthesis of (+/-)-monomorine I.