Synthesis and Oxidation of Internally Chlorinated Carbachlorins

Abstract

Chlorinated cyclohexene and cyclopentene dialdehydes, which can be prepared in one step from cyclohexanone or cyclopentanone, were condensed with a tripyrrane in the presence of trifluoroacetic acid and oxidized with DDQ to afford modest yields of internally halogenated carbachlorin‐type products. The new macrocycles retained strongly aromatic properties and gave UV/Vis spectra with intense Soret bands near 400 nm and moderately strong chlorin‐like absorptions at approximately 660 nm. Attempts to further oxidize a 21‐chlorocarbachlorin with DDQ in refluxing toluene gave a dehalogenated carbaporphyrin and two externally chlorinated products.

21-Carba-23-oxaporphyrinoids and 21-oxo-21-carba-23-oxaporphyrinoids: macrocyclic π-conjugation involving the carbonyl moiety

“…A pyrrole β-alkylated derivative containing β-unsubstituted cyclopentadiene and its palladium( ii ) complex were reported. 19,20 adj -Dicarbachlorin 3 is the first free base dicarbaporphyrinoid system with an internal methylene unit. 7…”

A meso‐Tetraaryl‐21‐carbaporphyrin: Incorporation of a Cyclopentadiene Unit into a Porphyrin Architecture

“…[10,11] Initially,the synthesis of an aromatic carbaporphyrin (3), which is b-substituted at the pyrrole rings,w as achieved by Berlin [12] and subsequently by Lash [13] by a[ 3 + +1] condensation. [14,15] adj-Dicarbachlorin (5)isthe first free-base carbaporphyrinoid system with an internal methylene unit. [14,15] adj-Dicarbachlorin (5)isthe first free-base carbaporphyrinoid system with an internal methylene unit.…”

“…Recently the pyrrole b-alkylated derivative containing a b-unsubstituted cyclopentadiene (4)a nd its palladium(II) complex were reported. [14,15] adj-Dicarbachlorin (5)isthe first free-base carbaporphyrinoid system with an internal methylene unit. [16] Ar ational synthesis of the 10,15-dimesityl-21carba-23-thiaporphyrin 6 and a2 1-carba-23-thiaporphyrin dimer with the dihydrofulvalene bridging motif were also elaborated.…”

A meso‐Tetraaryl‐21‐carbaporphyrin: Incorporation of a Cyclopentadiene Unit into a Porphyrin Architecture

“…Initially, the synthesis of an aromatic carbaporphyrin ( 3 ), which is β‐substituted at the pyrrole rings, was achieved by Berlin and subsequently by Lash by a [3+1] condensation. Recently the pyrrole β‐alkylated derivative containing a β‐unsubstituted cyclopentadiene ( 4 ) and its palladium(II) complex were reported . adj ‐Dicarbachlorin ( 5 ) is the first free‐base carbaporphyrinoid system with an internal methylene unit .…”