One-Pot Preparation of (NH)-Phenanthridinones and Amide-Functionalized [7]Helicene-like Molecules from Biaryl Dicarboxylic Acids

Abstract

A one-pot transformation of biaryl dicarboxylic acids to (NH)-phenanthridinone derivatives based on a Curtius rearrangement and subsequent basic hydrolysis was developed. This method is also applicable for the preparation of optically active amide-functionalized [7]helicene-like molecules. Furthermore, aza[5]helicene derivatives with a phosphate moiety were isolated as a product of the Curtius rearrangement step in the case of substrates that bear chalcogen atoms. The stereostructures of these products, revealed by X-ray diffraction analysis, suggested that chalcogen-bonding and pnictogen-bonding interactions might contribute to their stabilization. The configurational stability of the helicene-like molecules and their chiroptical properties were further investigated.

Syntheses, and Structural and Physical Properties of Axially Chiral Biaryl Dicarboxylic Acids Bearing Chalcogen Atoms

“…3(B). 18) This crystal structure exhibited a twisted biaryl system around the chiral axis with dihedral angles of 81.4(3)° (ϕa,bc,d) as reported previously (Fig. 3B(1)).…”

“…CD Spectra for Determination of the Absolute Configurations of 2 and 4 To determine the absolute configurations of 2 and 4, CD spectra of these compounds were measured and compared to those of (R)-and (S)-3, whose absolute configurations were determined by X-ray analysis in our previous report. 18) As shown in Fig. 5A, (R)-3 showed a negative Cotton effect from 256 to 237 nm, and a positive Cotton effect from 236 to 218 nm; its enantiomer (S)-3 showed a spectrum which was an exact mirror image of CH 3 CN.…”

“…Synthesis and Optical Resolution First, we examined the synthesis and optical resolution of binaphthoselenophene dicarboxylic acid 4 according to the preparation of 3 18) (Chart 1). Naphthoselenophene bromide 8 was prepared from the cyclization of 7 in the presence of SeO 2 according to the reported procedure.…”

“…Optical resolution with the enantiomeric amine (R,R)-9 gave (R)-4 in a similar manner. The absolute configuration of the axial chirality of 4 obtained with (S,S)-9 was determined to be S by its circular dichroism (CD) spectrum showing a similar Cotton effect to that of (S)-3, in which the absolute configuration was determined by X-ray analysis 18) as described below.…”

“…Catalyst 1 was prepared from axially chiral binaphthothiophene dicarboxyxlic acid 3 (Fig. 2) as a key intermediate 17,18) and the preparation of axially chiral dicarboxylic acids bearing chalcogen atoms are indispensable for developing a series of dirhodium carboxylate complexes. This background motivated us to investigate the syntheses, structural features, and physical properties of optically active dicarboxylic acids 2, 4, 5 [19][20][21] and 6 19) bearing oxygen and selenium atoms in their fused cyclic ring systems (Fig.…”