TY - DATA T1 - Synthesis of (−)-Sedinine by Allene Cyclization and Iminium Ion Chemistry PY - 2010/09/03 AU - Roderick W. Bates AU - Yongna Lu UR - https://acs.figshare.com/articles/journal_contribution/Synthesis_of_Sedinine_by_Allene_Cyclization_and_Iminium_Ion_Chemistry/2735929 DO - 10.1021/ol1016492.s002 L4 - https://ndownloader.figshare.com/files/4412668 KW - Allene Cyclization KW - semicyclic KW - bicyclic KW - cyclization KW - iminium ions KW - metathesi KW - hydroxylamine KW - allenic KW - silyl enol ether KW - consideration KW - conformation KW - Sedinine KW - acetal KW - synthesis KW - opening KW - conversion KW - Lewis acidic conditions KW - stereoselectivity KW - Iminium Ion Chemistry KW - tran KW - sedum alkaloid sedinine KW - Synthesi N2 - A synthesis of the sedum alkaloid sedinine has been achieved employing silver(I)-catalyzed allenic hydroxylamine cyclization and ring-closing metathesis to form a bicyclic N,O-acetal. Ring opening of this acetal with a silyl enol ether under Lewis acidic conditions is exclusively trans selective, leading to the natural product after reduction. On the other hand, conversion of the bicyclic N,O-acetal to a semicyclic N,O-acetal results in no stereoselectivity during such a reaction. The contrasting results can be rationalized by consideration of the conformation of the iminium ions. ER -