TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The conversion of (VIII) into (I) comprises deallylating (VIII) to give (3R,4S)-1-(4-fluoro-phenyl)-3-(3-(4-fluoro-phenyl)-3-oxo-propyl)-4-(4-hydroxy-phenyl)-azetidin-2-one (A2) and reducing the carbonyl group of (A2) in presence of a chiral reducing agent or reducing agent in presence of a chiral catalyst to form (I), where the deallylation is carried out in presence of 1,3-dicarbonyl compounds, ~b-ketoesters, 1,3-diketones, optionally substituted amines including morpholine or pyrrolidone, or alkali metal carbamate in presence of suitable transition metal catalyst, or using an acid catalyst comprising sulfonic or sulfuric acid catalyst including para-toluenesulfonic acid, benzene sulfonic acid or their salts, preferably para-toluenesulfonic acid or bases that include alkali metal carbonate including potassium carbonate, and the reducing agent is borane dimethyl sulfide complex, borane tetrahydrofuran complex, sodium borohydride, a substituted borohydride( chlorbenzyloxy-Proline)3-sodium borohydride, and chiral catalyst is (R)-2-methyl-Corey-Bakshi-Shibata(CBS)-oxazaborolidine, R-butyl CBS-oxazaborolidine, R-phenyl-CBS-oxazaborolidine, para-chlorodiisopinocamphenyl borane or by any known non-hydrogenolytic conditions. Preferred Components: In the step (a): the Lewis acid catalyst is titanium tetrachloride and/or titanium isopropoxide; the base includes organic base, which is tertiary amine comprising trialkyl amine, preferably N,N-diisopropylethylamine, triethylamine, tri-n-butylamine, tri-n-propylamine or tetramethylethylenediamine; the organic solvent includes aliphatic or aromatic hydrocarbon solvents comprising toluene, 1,2-xylene, 1,4-xylene, halogenated solvents including dichloromethane, 1,2-dichloroethane, chloroform, carbon tetrachloride, ethers including tetrahydrofuran, 2-methyl tetrahydrofuran, 1,2-dimethoxyethane and/or 1,2-diethoxyethane. In step (b); the silylating agents include N,O-bis(trimethylsilyl)acetamide, N-methyl-O-trimethylsilylacetamide, isopropenyloxy trimethyl silane, trimethylsilyl chloride; fluoride source includes tetra n-butylammonium fluoride, cesium fluoride, potassium fluoride, benzyltriethylammonium fluoride, benzyltrimethylammonium fluoride, phenyltriethylammonium fluoride, phenyltrimethylammonium fluoride or their hydrates; suitable solvent include ethers including alkyl or aryl or cyclic ether comprising tetrahydrofuran, 2-methyl tetrahydrofuran, methyl tert-butyl ether; aliphatic or aromatic hydrocarbons including toluene, 1,2-xylene or 1,4-xylene; alkyl- or allyl nitrile including acetonitrile, alkyl- or allyl ester including ethylacetate and/or halogenated solvent comprising dichloromethane. In step (c), the suitable base includes alkali or alkaline metal hydroxides, alkali or alkaline metal carbonates/ bicarbonates, hydrates and their alkoxides including lithium hydroxide, lithium hydroxide monohydrate, sodium hydroxide, sodium carbonate, sodium bicarbonate or potassium hydroxide, alcohols comprising methanol, ethanol, isopropanol, tertiary butanol, alkyl or aryl or cyclic ethers, which is tetrahydrofuran, 2-methyl tetrahydrofuran, dialkyl ethers or 3-6C ketones comprising acetone and/or methyl isobutyl ketone. In step (d), the base is organic base comprising primary, secondary or tertiary amines depending upon substitution including amine moiety of formula (NR5R6R7) (A1), inorganic bases including alkali or alkaline earth metal hydroxide, carbonates, bicarbonate, alkoxide or their hydrides. In step (e), the activating agent includes oxalyl chloride, phosphorus trihalide, phosphorus pentahalide, thionyl halide, organic acid halide comprising acetyl chloride, pivaolyl chloride, 2-8C alkyl chloroformate, aryl chloroformates, Lewis acid comprising boric acid or 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride or triazole including benzotriazole; the solvent comprises halogenated solvents including dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane; aliphatic esters including ethyl acetate, aliphatic or cyclic ether including tetrahydrofuran, 2-methyl tetrahydrofuran, 1,2-dimethoxyethane, 1,2-diethoxyethane, amide solvent including dimethylformamide, aliphatic or aromatic hydrocarbon solvent including toluene, 1,2-xylene and/or 1,4-xylene. In step (f), the catalyst includes transition metal salts or their complexes including metals, which are palladium, zinc, cerium or iron, palladium salts, iron(II) salts; iron(III) acetylacetonate, ferrous chloride, ferric chloride, zinc chloride, cerium(III) chloride, Pd(0) complexes, Cu(I) salts or tetrakis(triphenylphosphine) palladium and with or without additives, or ligands including N-methyl morpholine, N,N,N',N',-tetramethylethylene diamine, N,N,N',N',N'-tetramethyldiethylene triamine or bis(2- (N,N-dimethyl amine)ethyl)ether. The solvent includes aliphatic or aromatic hydrocarbon solvent comprising toluene, 1,2-xylene or 1,4-xylene, halogenated solvent including dichloromethane, 1,2-dichloroethane and aliphatic or cyclic ether including tetrahydrofuran, 2-methyl tetrahydrofuran, 1,2-dimethoxyethane and/or 1,2-diethoxyethane. Preferred Definitions:    R1 = phenyl;    R2, R3, R4 = H; and    Z = OH or 4-fluorophenyl.    EXAMPLE - To a solution of borane methyl sulfide complex (2.1 ml) and (R)-2-methyl- Corey-Bakshi-Shibata (CBS)-oxazoborolidine (1.12 ml) in dichloromethane at 0?oC under nitrogen atmosphere, 4-(4-allyloxy-phenyl)-1-(4-fluoro-phenyl)-3-(3-(4-fluoro-phenyl)-3-oxo-propyl)-azetidin-2-one (1 g) in dichloromethane in dichloromethane (30 ml) was added slowly at 0-5?oC. The reaction mixture was stirred till completion of the reaction. Methanol (4 ml) and 5% aqueous hydrogen peroxide solution (50 ml) were added to the reaction mixture and stirred at 25-30?oC for 15 minutes. The organic layer was separated, successively washed with 1 N hydrochloric acid solution (50 ml) and brine (50 ml) and dried over sodium sulfate. The solvent was distilled off completely under reduced pressure to give 4-(4-allyloxy-phenyl)-1-(4-fluoro-phenyl)-3-((3S)-3-(4-fluoro-phenyl)-3-hydroxy-propyl)-azetidin-2-one (D1). To a solution of (D1) and 5,5-dimethyl-1,3-cyclohexanedione (6.2 g) in tetrahydrofuran (200 ml), tetrakis (triphenylphosphine) palladium(0) (0.15 g) was added at 25-30?oC and the reaction mass was heated with vigorous refluxing under nitrogen gas atmosphere. After completion of the reaction, the mixture was cooled to 25-30?oC, and poured into 10% sodium carbonate solution (200 ml) and extracted with ethyl acetate (200 ml). The organic layer was separated and washed successively with 10% aqueous sodium carbonate solution (2x 200 ml), demineralized water (200 ml) and dried over sodium sulfate. The solvent was distilled off completely under reduced pressure to give ezetimibe.