The Dawn of Functional Organoarsenic Chemistry

Abstract

Organoarsenic chemistry was actively studied until the middle of 20th century. Although various properties of organoarsenic compounds have been computationally predicted, for example, frontier orbital levels, aromaticity, and inversion energies, serious concern to the danger of their synthetic processes has restricted experimental studies. Conventional synthetic routes require volatile and toxic arsenic precursors. Recently, nonvolatile intermediate transformation (NIT) methods have been developed to safely access functional organoarsenic compounds. Important intermediates in the NIT methods are cyclooligoarsines, which are prepared from nonvolatile inorganic precursors. In particular, the new approach has realized experimental studies on conjugated arsenic compounds: arsole derivatives. The elucidation of their intrinsic properties has triggered studies on functional organoarsenic chemistry. As a result, various kinds of arsenic-containing π-conjugated molecules and polymers have been reported for the last few years. In this minireview, progress of this recently invigorated field is overviewed.

From a 2,1‐Benzazaarsole to Elusive 1‐Arsanaphthalenes in One Step

“…[1][2][3][4][5] Despite recent progress involvingthe heavier congener arsenic, [6][7][8][9][10][11][12] many relatively trivial arsenic heterocycless till remain elusive despitee xhibiting remarkable physical-chemical properties. [1,13] For example,a nd in contrast to arsinine reported by Ashe [14] and 9arsaanthracene independently synthesized by Jutzi [15] and Bickelhaupt, [16] structurally characterized1-arsanaphthalenes (i.e. arsinolines, Figure 1A)a re unknown at this point in time.…”

Dibenzoarsepins: Planarization of 8π‐Electron System in the Lowest Singlet Excited State

“…[11d,13] Recently,w eh ave developed simple synthetic methodologies using cyclooligoarsines such as pentamethylpentacycloarsine (1-Me)a nd hexaphenylhexacycloarsine (1-Ph) [14] as shown in Scheme 1. [15] When the AsÀAs bonds of these cyclooligoarsines are cleaved, reactive species such as radicals,e lectrophiles,a nd nucleophiles are generated in situ. [16] Diiodoarsines (2-Me and 2-Ph)were then prepared by the addition of iodine to the cyclooligoarsines,and they could be used for the construction of the cyclic arsepin core with ad ilithio intermediate.…”

Dithieno[3,4‐b:3',4'‐d]arsole: A Novel Class of Hetero[5]radialenes

“…[11] This strategy allowed us to circumvent usage of volatile and toxic arsenic intermediates such as phenylarsine and dichlorophenylarsine, which are required for traditional synthetic routes toward organoarsenic compounds. [12] The THF solution of the generated diiodophenylarsine was employed for the reaction with 4,4′dilithio-3.3′-bithiophene, which was given from the dibromide precursor. The product was isolated by alumina column chromatography and recrystallization from dichloromethane and methanol.…”