The new approach for the preparation of P,P-disubstituted pyrroles presented here opens up a rational, and multifacetted direct route to porphyrins with a three-dimensionally structured periphery. This has led to the preparation of the first biconcave metalloporphyrins, whose frameworks promise interesting catalyst properties.E-xperinien f a1 Procedure 1: Acetylcnedicarbonitrile (234 mg, 3.08 mmol) in benzene ( 5 mL) was added dropwise over 4 h (under N2) to a heated (XO'C) suspension of 2,3,6,7-tetramethylanthracene (452 mg. 1.93 mmol) [IS] in benzene ( 5 mL). The reaction mixture was heated under retlux for an additional 10 h. After cooling and concentration of the mixture. column chromatography (silica gel, CH,Cl,/petroleum ether 1/1) and crystalliration from CH,CI, yielded 562 mg (1.81 mniol, 94%) I. 2: DlBAH (12 mmol. 1 M in hexane) was treated with 1 (0.60 g. 1.93 mmol) in dry CH2CI, (20 mL) under N, at ~ 20 C and stirred. The mixture was stirred at -20°C for 3.5 h. treated with aqueous citric acid ( 0 . 5~. 16 mL) and diluted with aqueous citric acid (0.5 M. 12 mL) and CH,CI, (12 mL) at room temperature. The organic phase was concentrated and purified by column chromatography (silica gel, CH,CI,:petroleum ether I l l ) . The colorless pyrrole 2 (190.5 mg, 0.64 mmol) crystallized from CH2C12/hexane (1 ' 5 ) in 33% yield. 3 . A solution of2 181 mg. 0.27 mmol) in CH2CI, (0.6 mL) was treated under N, with CH,OH (0.84 mL). aceticacid (78 pL). and 30% formaldehyde solution (111 pL). The mixture has protected from light, stirred for 7 d at room temperature under N,, and then concentrated. The residue was dissolved in benzene (2 mL) under N, and treated Mith dichlorodicyanobenzoquinone (DDQ) (42.3 mg, 0.18 mmol) in ben-Lene (4 mL). After2.5 h a t room temperature, the solution wasdiluted with CH,CI, (7 mL) and shaken with phosphate buffer (pH 7) (0.
