72039-82-8Relevant academic research and scientific papers
Construction of Pentacyclic Limonoid Skeletons via Radical Cascade Reactions
Mutoh, Hiroyuki,Nakamura, Shu,Hagiwara, Koichi,Inoue, Masayuki
, p. 6869 - 6878 (2021/05/29)
Limonoids 1 and 2 share a 6/6/6/5-membered ABCD-ring system and a six-membered oxacycle and differ in their C9-stereochemistries. A new radical-based strategy was devised to construct the pentacyclic skeletons of 1 and 2. An oxacycle-fused A-ring and enyne fragments were coupled to produce radical precursors 4a-4c with different C7-oxygen functionalities. The bridgehead tertiary bromide of 4a-4c participated in a radical cascade reaction with the three unsaturated bonds to cyclize the C9-diastereomeric BCD-rings.
Total Synthesis of (-)-Chromodorolide B by a Computationally-Guided Radical Addition/Cyclization/Fragmentation Cascade
Tao, Daniel J.,Slutskyy, Yuriy,Muuronen, Mikko,Le, Alexander,Kohler, Philipp,Overman, Larry E.
supporting information, p. 3091 - 3102 (2018/03/08)
The first total synthesis of a chromodorolide marine diterpenoid is described. The core of the diterpenoid is constructed by a bimolecular radical addition/cyclization/fragmentation cascade that unites two complex fragments and forms two C-C bonds and four contiguous stereogenic centers of (-)-chromodorolide B in a single step. This coupling step is initiated by visible-light photocatalytic fragmentation of a redox-active ester, which can be accomplished in the presence of an iridium or a less-precious electron-rich dicyanobenzene photocatalyst, and employs equimolar amounts of the two addends. Computational studies guided the development of this central step of the synthesis and provide insight into the origin of the observed stereoselectivity.
