Total Synthesis of Lamellarins G, J, L, and Z Using One-Pot Halogen Dance/Negishi Coupling
Kazuki Morii1, Yuto Yasuda1, Daiki Morikawa1
1Department of Chemical Science and Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan.
Abstract:
A bottom-up synthesis of lamellarins G, J, L, and Z was achieved via one-pot halogen dance/Negishi coupling of a lithiated dibromopyrrole derivative. The easily accessible dibromopyrrole bearing an ester moiety underwent halogen dance smoothly at -78 °C within 10 min. The resultant α-pyrrolyllithium was transmetalated to the corresponding organozinc species, which was then coupled with an aryl iodide in the presence of catalytic palladium to provide the fully substituted pyrrole. Subsequent halogen-lithium exchange was performed to incorporate a boronate group exclusively at the β position proximal to the ester moiety. This synthetic intermediate allowed stepwise diarylation for the total synthesis of lamellarins G, J, L, and Z.
More Related Videos
07:36Versatile CO2 Transformations into Complex Products: A One-pot Two-step Strategy
Published on: November 9, 2019
10:17Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of α-Imino γ-Lactones and Alkylidene Pyrazolones
Published on: February 7, 2019
Related Concept Videos
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
[3,3] Sigmatropic Rearrangement of 1,5-Dienes: Cope Rearrangement
Ziegler–Natta Chain-Growth Polymerization: Overview
Preparation of Alkynes: Dehydrohalogenation
Alkynes can be prepared by dehydrohalogenation of vicinal or geminal dihalides in the presence of a strong base like sodium amide in liquid ammonia. The reaction proceeds with the loss of two equivalents of hydrogen halide (HX) via two successive E2 elimination reactions.
Preparation of Diols and Pinacol Rearrangement
The reaction begins with transferring a proton from the acid catalyst to one of the hydroxyl groups, producing an oxonium ion.
Acid Halides to Amides: Aminolysis
In the first step of the aminolysis mechanism, the amine attacks the carbonyl carbon of the acyl chloride to form a tetrahedral intermediate. In the second step, the carbonyl group is re-formed with the elimination of a chloride...
