One-Pot Synthesis of Hypervalent Diaryl(iodo)bismuthanes from o-Carbonyl Iodoarenes by Zincation

Toshihiro Murafuji,Daiki Magarifuchi,Masahiro Narita,Katsuya Ishiguro,Isamu Miyakawa,A F M Hafizur Rahman,Shin Kamijo

doi:10.1155/2019/2385064

Abstract

Diaryl(iodo)bismuthanes possessing a hypervalent C=O•••Bi–I bond were conveniently synthesized in a one-pot reaction by using arylzinc reagents generated from o-carbonyl iodobenzenes and zinc powder under ultrasonication. This method is superior to the conventional organolithium and Grignard methods because it has a wide functional group tolerance, requires no protecting group manipulations, and proceeds under mild reaction conditions that do not need low temperature control. Furthermore, no intermediate triarylbismuthane precursor for the hypervalent iodobismuthane is necessary.

Highlights

Much effort has been devoted to the study of hypervalent bismuth(III) compounds [1,2,3,4,5]
The acetyl substituent of acetophenone is incompatible with BuLi, meaning that the synthesis of started from the protected silyl enol ether, and the harsh reaction conditions requiring excess BuLi caused the loss of Ar2BiCl or the decomposition of the product, lowering the reproducibility of the yield [13, 14]
The arylzinc was prepared by using the method reported by Takagi and coworkers [20], who treated iodoarenes containing an electron-withdrawing substituent, such as a methoxycarbonyl or an acetyl substituent, at the ortho position in the presence of zinc powder under ultrasonication at 30∘C

Summary

Introduction

Much effort has been devoted to the study of hypervalent bismuth(III) compounds [1,2,3,4,5]. Compounds and , which possess diary sulfone and acetophenone molecular scaffold, respectively, exhibited high antifungal activities. These compounds are synthesized by directed ortholithiation (Scheme 1). To facilitate the search for active antifungal compounds, a general and convenient synthetic method that has wide functional group compatibility for introducing various molecular scaffolds to the bismuth(III) center is required. The imino and ester substituents were tolerated despite their polarized double bond, required protection of the formyl substituent and needed low-temperature control Based on these results, we investigated using a type of organometallic reagent that is less reactive than Grignard reagents. The organozinc method was superior to our previously reported organolithium and Grignard methods owing to the high functional group tolerance, short synthesis, mild reaction conditions, and acceptable yields

Materials and Methods

Results and Discussion

Conclusions