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An environmentally benign, practically scalable and highly selective C-arylalkylation of active methylene compounds is developed using CTAB as the inverse phase transfer catalyst in water. The methodology developed is elaborated into the one-pot synthesis of quinoline derivatives and also applicable to the regioselective N-aralkyl of 2-pyridones.

A series of new hydroxamic acid derivatives (6a-f) at C-3 position of fluoroquinolones were designed and synthesized through multistep synthesis. The design concept involved replacement of the 3-carboxylic acid in fluoquinolones with hydroxamic acid as an acid mimicking group. The synthetic work employed in this work provides a good example for the synthesis of pure hydroxamic acid based fluoroquinolones. The synthesized compounds were characterized by (1)H-NMR, electrospray ionization (ESI)-MS and IR. The new compounds were tested for their in vitro antimicrobial and anti-proliferative activity. Out of the six derivatives, compound 6e exhibited moderate antibacterial activity by inhibiting the growth of Escherichia coli and Klebsiella pneumoniae (MIC: 4.00-8.00 µg/mL). Compounds 6b and 6f displayed good growth inhibition against A549 Lung adenocarcinoma and HCT-116 Colon carcinoma cell lines.

A series of new hydroxamic acid derivatives (VI) (6 examples) are designed, synthesized, and evaluated for their in vitro antibacterial and antiproliferative activities.

In arene–tricarbonylchromium complexes, exo-selectivity is the normal. This account, on the other hand, summarizes our results of endo-selective nucleophilic additions with very high stereocontrol at relatively remote sites, which enhances the potential of these complexes as synthons for target synthesis.

Stereoselective annulations on Cr(CO)3 complexed tetralone and benzosuberone§ derivatives have been achieved. Diastereomeric products are shown to be related by an epimerisable chiral centre. An unusually facile de-ethoxycarbonylation has been observed.

Conjugate addition of nitromethane to 2-arylidene-1-tetralones anchored on Cr(CO) 3 was found to be about 100% stereoselective.

Cyclopropanation of 2-arylidene-1-tetralone tricarbonylchromium complexes with dimethylsulfoxonium methylide under phase-transfer catalysis condition provided cyclopropanes exclusively from the endo-face.

Stereoselective annulations on Cr(CO)3 complexed tetralone and benzosuberone§ derivatives have been achieved. Diastereomeric products are shown to be related by an epimerisable chiral centre. An unusually facile de-ethoxycarbonylation has been observed.

In arene–tricarbonylchromium complexes, exo-selectivity is the normal. This account, on the other hand, summarizes our results of endo-selective nucleophilic additions with very high stereocontrol at relatively remote sites, which enhances the potential of these complexes as synthons for target synthesis.

Efficient diastereocontrol is achieved in Hosomi-Sakurai reaction of flexible acyclic enones anchored on arene­ tricarbonylchromium template. Relative stereochemistry of groups in the products is compared with those obtained by al­ lylmagnesium bromide addition followed by an anionic oxy-Cope rearrangement. The results indicate an endo-selective conjugate addition dictated by an out-of-plane bound Lewis acid in the Hosomi-Sakurai reaction, similar to the trend estab­ lished earlier for rigid substrate structures. We recently reported I an unusual , endo-selective, conjugate allylation on 2-arylidene-1-tetralone tricar­ bonylchromium complex 2 by Hosomi-Sakurai reac­ tion 3 . In this stereochemically well-defined substrate, the expected in-plane coordination of Lewis acid to the ketone carbonyl group was thought to be pre­ vented by two flanking hydrogens, the peri proton of the aromatic ring of tetralone and the l3-olefinic pro­ ton, held in a rigid framework. As a result, the Lewis acid was forced to coordinate in an out-of-plane man­ ner from the more accessible exo face, which in tum blocked approach of reagent from the same face. The net effect was an endo-selective allylation (Scheme I). The same concept was subsequently ex­ ploited to predictably induce endo-selective nucleo­ philic additions of organolithium 4 and organomagne­ sium 5 reagents to such substrates in presence of Lewis acids. In flexible, acyclic analogues, a rotation about the C(O)-alkene bond leading to cisoid (I and II) or tran­ soid (III) orientation of the enone (Chart 1) can jeop­ ardize diastereoselectivity. It may be noted, however, that the steric inhibition offered by the flanking hy­ drogens in I or II (cisoid orientation) would still ad

Conjugate addition of nitromethane to 2-arylidene-1-tetralones anchored on Cr(CO) 3 was found to be about 100% stereoselective.

In arene-tricarbonylchromium complexes, excellent diastereocontrol at benzylic or homobenzylic sites can be achieved since the Cr(CO)3 group effectively blocks one face of the molecule and prevents approach of reagents from this direction.1 This feature has been widely utilized in designing useful synthetic strategies.2 Suitably structured substrates allow almost total diastereoselectivity even three carbons away from the complexed aromatic ring.3 In most of these instances, the reaction occurs from the exo face, i.e., the face opposite to the metal; endo-selective reactions are particularly rare.4 Herein we wish to report a completely endo-selective Hosomi-Sakurai allylation5 on the 2-arylidene-1-tetralone-Cr(CO)3 complex. The corresponding exo-adduct was obtained by an alternative sequence of reactions. In addition to displaying an unusual stereochemical preference, the TiCl4-catalyzed allylation reaction provides a prima facie evidence of out-of-plane coordination of titanium to the ketone dictating steric course of the reaction.

Cyclopropanation of 2-arylidene-1-tetralone tricarbonylchromium complexes with dimethylsulfoxonium methylide under phase-transfer catalysis condition provided cyclopropanes exclusively from the endo-face.