Loading...
Synthetic approaches to the skeleton of crinine-type alkaloids from isoquinoline and the total synthesis of (?)-crinine
Citations
Altmetric:
Soloist
Composer
Publisher
[Fort Worth, Tex.] : Texas Christian University,
Date
2010
Additional date(s)
Abstract
The crinine-type alkaloids, which have the 5,10b-ethanophenanthridine skeleton as the core structure, represent an important sub-class of the family of Amaryllidaceae alkaloids. Considering the obvious structural relationship between the crinine-type alkaloids and the isoquinoline nucleus, a synthetic strategy involving the construction of the crinane skeleton from isoquinoline would be a logical approach. In order to realize this goal, a novel methodology to prepare 4,4-disubstituted 1,4-dihydroisoquinolines through boron-activated enamine chemistry has been developed in our lab. This method provides not only a quaternary carbon center at C-4 but also an imine group that can be further functionalized. A systemic investigation of the reductive alkylation of isoquinoline using boron-activated enamine chemistry was performed in order to examine the scope of this methodology for preparing 4,4-disubstituted isoquinoline derivatives. Various functional groups including simple alkyls, allyl, protected alcohols, protected aldehydes, and esters were successfully introduced at C-4 of the 1,4-dihydroisoquinoline product. Additionally, several spiro compounds and imines with two different substituents at C-4 were also synthesized. Based on this method, (?)-crinine was efficiently prepared in 9 steps in 14.4% overall yield for the first time from 6,7-methylenedioxyisoquinoline using an AB-->D-->C sequence. This method was then applied to build the skeletons of delagoenine and delagoensine - two very unusual alkaloids possessing a hemiaminal function in the D-ring.
Contents
Subject
Subject(s)
Alkaloids.
Isoquinoline.
Organic compounds Synthesis.
Isoquinoline.
Organic compounds Synthesis.
Files
Loading...
Bian.pdf
Adobe PDF, 12.77 MB
Research Projects
Organizational Units
Journal Issue
Genre
Dissertation
Description
Format
Department
Chemistry and Biochemistry
Advisor
Minter, David E.