Potharaju Raju

Synthetic Utility of Arylmethylsulfones: Annulative π-Extension of Aromatics and Hetero-aromatics Involving Pd(0)-Catalyzed Heck Coupling Reactions

A straightforward and general method for the synthesis of annulated thiophene, dibenzothiophene, and carbazoles analogues has been achieved involving alkylation of 2-bromo-1-(phenylsulfonylmethyl)arene/heteroarene with arylmethyl bromides/heteroarylmethyl bromides using t-BuOK as a base in DMF, followed by Pd(0)-mediated intramolecular Heck coupling in the presence of K2CO3 in DMF at 80-140 °C. The attractive feature of this protocol is that a wide variety of π-conjugated heterocycles could be readily accessed by an appropriate choice of arylmethylsulfones and benzylic bromides.

Crystal structure of N-{[3-bromo-1-(phenyl-sulfon-yl)-1H-indol-2-yl]meth-yl}benzene-sulfonamide.

In the title compound, C21H17BrN2O4S2, the indole ring system subtends dihedral angles of 85.96 (13) and 9.62 (16)° with the planes of the N- and C-bonded benzene rings, respectively. The dihedral angles between the benzene rings is 88.05 (17)°. The molecular conformation is stabilized by intramolecular N—H⋯O and C—H⋯O hydrogen bonds and an aromatic π–π stacking [centroid-to-centroid distance = 3.503 (2) Å] interaction. In the crystal, short Br⋯O [2.9888 (18) Å] contacts link the molecules into [010] chains. The chains are cross-linked by weak C—H⋯π interactions, forming a three-dimensional network.

Crystal structure of 2-[2-phenyl-1-(phenyl-sulfon-yl)eth-yl]-1-phenyl-sulfonyl-1H-indole.

In the title compound, C28H23NO4S2, the indole ring system (r.m.s. deviation = 0.007 Å) subtends dihedral angles of 78.69 (13) and 38.97 (13)° with the planes of the N- and C-bonded sulfonylbenzene rings, respectively, and these two benzene rings are inclined to each other at an angle of 65.45 (16)°. The methylene-linked phenyl ring is twisted at an angle of 81.80 (13)° from the indole ring. The molecular structure features two short intramolecular C—H⋯O contacts, which both generate S(6) rings. In the crystal, molecules are linked by C—H⋯O hydrogen bonds and C—H⋯π interactions, generating a three-dimensional network.

Crystal structure of ethyl 2-phenyl-9-phenyl-sulfonyl-9H-carbazole-3-carboxyl-ate.

In the title compound, C27H21NO4S, the dihedral angles between the carbazole ring system (r.m.s. deviation = 0.015 Å) and the sulfur-bonded and directly linked benzene rings are 79.98 (11) and 53.51 (18)°, respectively. The benzene rings subtend a dihedral angle of 48.4 (2)°. The ethyl side chain of the ester group has an extended conformation [C—O—C—C = −172.3 (3)°]. In the crystal, inversion dimers linked by pairs of weak C—H⋯O hydrogen bonds generate R 2 2(22) loops. The dimers are linked by weak C—H⋯π and π–π [centroid-to-centroid distances ranging from 3.5042 (14) to 3.888 (2) Å] interactions, thereby forming a three-dimensional supramolecular network.

Crystal structure of (E)-2-(4-meth­oxy­styr­yl)-3-methyl-1-phenyl­sulfonyl-1H-indole

In the title compound, C24H21NO3S, the dihedral angles between the indole ring system (r.m.s. deviation = 0.030 Å) and the sulfur and ethylene-bonded benzene rings are 80.2 (2) and 49.29 (15)°, respectively. The dihedral angle between the pendant benzene rings is 37.7 (2)°. In the crystal, molecules are linked by C—H⋯O hydrogen bonds and weak C—H⋯π and π–π [centroid-to-centroid distances = 3.549 (2) and 3.743 (3) Å] interactions, forming a three-dimensional network.

Crystal structure of (E)-diethyl 2-[(1-phenyl-sulfonyl-1H-indol-3-yl)methyl-idene]succinate.

In the title compound, C23H23NO6S, the phenyl ring is perpendicular [dihedral angle = 89.34 (9)°] to the indole ring system. In the molecule, the ethoxy groups are each disordered over two sets of sites with occupancy ratios of 0.671 (6):0.329 (6) and 0.75 (3):0.25 (3). The molecular conformation is consolidated by a weak C—H⋯O interaction, which generates an S(6) graph–set motif. The packing of the molecules in the crystal structure features weak C—H⋯π interactions.