Although marine ladder polyethers are extremely toxic compounds, they are also known to have antifungal and anticancer properties. The biosynthesis of these compounds is proposed to occur via an epoxide-opening cascade reaction, and several biomimetic reactions have been developed to synthesize portions of these molecules. In general, a cascade reaction is a consecutive series of chemical reactions that proceed via reactive intermediates and create multiple new bonds in one sequential process. These reactions allow for the rapid creation of molecular complexity and provide a more efficient synthetic route than building a molecule in an iterative fashion. In particular, the cascade reaction described in this proposal will enable the synthesis of fused polyether ring systems with 1,3-diaxial methyl groups, a motif that is present in many ladder polyethers. Despite the prevalence of this motif in these compounds, no cascade reactions have been reported that create rings containing this substitution pattern. This proposal also describes the application of this cascade reaction to the synthesis of a portion of brevisulcenal F and several other marine ladder polyethers. Brevisulcenal F is a marine ladder polyether natural product that was identified as a component of a harmful algal bloom (HAB) off the coast of New Zealand in 1998. It is one of the largest and most toxic marine polyethers that has been isolated. Therefore, its synthesis would provide material to study its unique bioactivity and determine possible applications for treating disease. Importantly, gambierol, a related ladder polyether, has been used as a chemical probe to study receptors implicated in the molecular basis of Alzheimer's disease. In this proposal, a strategy for the synthesis of the B-D and F-I rings of brevisulcenal F is outlined in which several rings are created iteratively, and the cascade process is then applied to the synthesis of the remaining rings. A similar strategy is presented for portions of maitotoxin, gambierol, gambieric acid A, and brevetoxin B. It is expected that the success of this proposal will set the stage for the total synthesis of these molecules and provide material to study their mechanisms of action.

Public Health Relevance

Red tide, also known as a harmful algal bloom (HAB), is the cause of fish kills and human poisoning worldwide. Although they are extremely toxic, the chemical components of these HAB's also have antifungal and anticancer properties, and some have been used to study Alzheimer's disease. This proposal describes a new strategy for efficiently synthesizing several of these compounds so that their biological activity can be better understood.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
5F32GM108181-03
Application #
8995667
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Lees, Robert G
Project Start
2014-02-01
Project End
2016-06-01
Budget Start
2016-02-01
Budget End
2016-06-01
Support Year
3
Fiscal Year
2016
Total Cost
Indirect Cost
Name
Massachusetts Institute of Technology
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
001425594
City
Cambridge
State
MA
Country
United States
Zip Code
Katcher, Matthew; Jamison, Timothy F (2018) Studies toward brevisulcenal F via convergent strategies for marine ladder polyether synthesis. Tetrahedron 74:1111-1122
Seo, Hyowon; Katcher, Matthew H; Jamison, Timothy F (2017) Photoredox activation of carbon dioxide for amino acid synthesis in continuous flow. Nat Chem 9:453-456