The synthesis of some novel stilbene dimers incorporating diamide tethers: studies in single electron transfer oxidation (FeCl3).

Maryam Sadat Alehashem,Noel F Thomas,Azhar Ariffin,Amjad Ayad Qatran Al-Khdhairawi

doi:10.1039/c7ra12534h

Maryam Sadat Alehashem, Noel F Thomas + Show 2 more

Open Access

https://doi.org/10.1039/c7ra12534h

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Abstract

The FeCl3 oxidative cascade reaction of the acetamido stilbene 1 which we reported some years ago produced the first atropodiastereomeric indolostilbene hybrid 3. By contrast, recent investigation of the oxidation of the stilbene succinamide dimer 72 (FeCl3/CH2Cl2) appears, on the basis of spectroscopic evidence, to have produced the bridged macrocyclic indoline 73.

Highlights

Some years ago we discovered that the 3,5-dimethoxy substituted acetamido stilbene, 1 when exposed to FeCl3 in CH2Cl2 proceeded in a mechanistically complex reaction to yield four products,[1] one of which was, unprecedented.This atropodiastereoselective transformation gave rise to a product 3 incorporating a stilbene, an indole, a chlorodimethoxyphenyl substituent, two stereogenic axes and an intramolecular hydrogen bond resulting in a 14-membered pseudomacrocycle in the conformation shown, 3 (Scheme 1)
These alternatives notwithstanding, we opted for a revised strategy. In this approach the amino stilbene monomer was constructed by the Heck procedure followed by a double acylation with the appropriate diacid chloride
Similar conditions were exploited by Heck in the course of a synthesis of a more functionalized version of our amino stilbene

Summary

Introduction

Some years ago we discovered that the 3,5-dimethoxy substituted acetamido stilbene, 1 when exposed to FeCl3 in CH2Cl2 proceeded in a mechanistically complex reaction to yield four products,[1] one of which was, unprecedented This atropodiastereoselective transformation gave rise to a product 3 incorporating a stilbene, an indole, a chlorodimethoxyphenyl substituent, two stereogenic axes and an intramolecular hydrogen bond resulting in a 14-membered pseudomacrocycle in the conformation shown, 3 (Scheme 1). To the best of our knowledge, no stilbene dimers incorporating diamide ethers based on succinamide or adipoylamide have been reported and studied from the point of view of FeCl3 promoted cyclisations This brings us to the section where this novel concept is described (our synthetic plan)

The synthetic plan

Results and discussion

Conclusion

Experimental