Furan-Terminated <i>N</i>-Acyliminium Ion Initiated Cyclizations in Alkaloid Synthesis
作者:Steven P. Tanis、Melissa V. Deaton、Lisa A. Dixon、Mark C. McMills、Jeffrey W. Raggon、Mark A. Collins
DOI:10.1021/jo980718l
日期:1998.10.1
cyclizations for the synthesis of linearly fused alkaloid precursors (Figure 2) is presented. The outcome of the cyclization event depends on the position of furan tether attachment (2 vs 3), tether length, and furan 5-substituent (R = H, CH(3), Ar). 3-Substitutedfurans cyclized to form 6- and 7-membered ring containing furans 35-38, 50, and 51 in good to excellent yields. 2-Substituted furans closed to form
Organocatalytic Enantioselective Functionalization of Cyclic α-Hydroxyamides: Access to Chiral Cyclic Imides and Azapolycyclic Compounds
作者:Xiao-Qian Zhang、Yuan-Ren Ma、Yan-Kai Liu
DOI:10.1021/acs.orglett.3c03182
日期:2023.11.24
convert unfunctionalized cyclic α-hydroxyamides into chiral cyclic α-hydroxyamides by reacting with vinyl sulfones, which could be used as versatile azacyclic synthons in the following sequences: (1) as the precursors of cyclic N-acyliminium ions to prepare natural productlike chiral azapolycyclic compounds under acidic conditions and (2) to construct chiral cyclicimides bearing unilateral substituents