Tandem Nucleophilic Addition/Oxy-2-azonia-Cope Rearrangement for the Formation of Homoallylic Amides and Lactams: Total Synthesis and Structural Verification of Motuporamine G
作者:Lijun Zhou、Zhiming Li、Yue Zou、Quanrui Wang、Italo A. Sanhueza、Franziska Schoenebeck、Andreas Goeke
DOI:10.1021/ja310002m
日期:2012.12.12
oxy-2-azonia-Cope rearrangements give homoallylic amides. In the case of 2-vinylcycloalkanones, the process results in ring enlargement, providing a novel route to 9- to 16-membered lactams. The preparative significance of this protocol was evidenced by a short synthesis of macrocyclic alkaloid motuporamine G. The stereochemistry-defining step of this oxy-azonia-Cope rearrangement was further studied
Photocleavage of carbon-tin bond activated by neighboring carbonyl group
作者:Tadashi Sate、Kohji Takezoe
DOI:10.1016/0040-4039(91)80612-a
日期:1991.8
β-Stannyl ketones underwent various types of reaction upon UV-irradiation, depending upon the substitution pattern of the substrate, and upon the solvent used.
Conceptually different: This allyltransfer reaction is catalyzed by Lewis acids (LAs) and proceeds atom‐economically by disproportionation of the carbonyl groups through organized oxonia‐Cope transition states (see scheme). A stereoselective [n+4] ring enlargement leads to a variety of macrolides with 9‐ to 16‐membered rings.
概念上的不同:烯丙基转移反应是由路易斯酸(LAs)催化的,并且通过有组织的oxonia-Cope过渡态使羰基歧化,从而在原子经济上进行(参见方案)。立体选择的[ n +4]环扩大会生成具有9至16元环的各种大环内酯类化合物。
Transannular Enantioselective (3 + 2) Cycloaddition of Cycloalkenone Hydrazones under Brønsted Acid Catalysis
作者:Jana Sendra、Efraim Reyes、Liher Prieto、Elena Fernández、Jose L. Vicario
DOI:10.1021/acs.orglett.1c03190
日期:2021.11.19
Hydrazones derivedfrom cycloalkenones undergo an enantioselective transannular formal (3 + 2) cycloaddition catalyzed by a chiral phosphoric acid. The reaction provides high yields and excellent stereocontrol in the formation of complex adducts with one or two α-tertiary amine moieties at the ring fusion, and these can be converted into very versatile stereodefined decalin- or octahydro-1H-indene-derived