NOVELTY - Asymmetric synthesis of venlafaxine comprises: (a) reacting anisaldehyde with nitromethane; (b) Michael addition of nitro styrene in presence of proline based organocatalyst; (c) reducing nitro ketone to get amine methoxyphenyl-nitroethylcyclohexane-1-ol which on nitro reduction to obtain amino-(methoxyphenyl)ethylcyclohexane-1-ol; (d) treating amino alcohol with e.g. mesyl chloride to get cyclohexenyl-(methoxyphenyl)ethylcarbamate (d1); (e) reacting (d1) with e.g. sodium hydride; (f) epoxidizing benzyl cyclohexenyl-methoxyphenylethylmethylcarbamate; and (g) selective epoxide opening.    USE - The process is useful for asymmetric synthesis of enantiomerically pure venlafaxine (claimed) that is used for treating major depressive and generalized anxiety disorders. No biological data given.    ADVANTAGE - The process: provides an 21-58% enantiomerically pure (-)- venlafaxine and 97-99% enantioselectivity of venlafaxine and enantiomeric excess of greater than or equal to 99% (claimed); is commercially cheap and utilizes easily available starting materials; utilizes cheap and environmentally friendly catalyst; and avoids expensive metal based catalysts, additional steps involving resolution of enantiomers.    DETAILED DESCRIPTION - Asymmetric synthesis of enantiomerically pure venlafaxine comprises: (a) reacting anisaldehyde with nitromethane in 1:11.8 mole ratio in presence of ammonium acetate in acetic acid under sonication at room temperature of 25-35 degrees C for 2-4 hours to obtain nitro styrene; (b) Michael addition of nitro styrene with cyclohexanone in mole ratio of 1:5 in presence of proline based organocatalyst under stirring at room temperature for 23-25 hours in the presence of p-toluene sulfonic acid to obtain nitro ketone; (c) reducing nitro ketone using sodium borohydride in tetrahydrofuran and water at 9:1 to obtain crude alcohol (2S)-2-((R)-1-(4-methoxyphenyl)-2-nitroethyl)cyclohexane-1-ol which on subjecting to nitro reduction by nickel(II) chloride hexahydrate and sodium borohydride in methanol as solvent to afford amine (2S)-2-((R)-2-amino-1-(4-methoxyphenyl)ethyl)cyclohexane-1-ol which on in situ protection by benzylchloroformate in presence of triethylamine as a base furnishes carboxy benzyl protected amino alcohol benzyl ((2R)-2-((1S)-2-hydroxycyclohexyl)-2-(4-methoxyphenyl)ethyl)carbamate; (d) treating amino alcohol of step (c) with mesyl chloride in presence of triethyl amine as a base in dichloromethane solvent under reflux condition at 40-45 degrees C for 14-25 hours to give crude mesylated reaction mixture which further on treatment with 1,8-diazabicyclo(5.4,0)undec-7-ene in acetonitrile solvent furnishes selectively more substituted double bond product benzyl (R)-(2-(cyclohex-1-en-1-yl)-2-(4- methoxyphenyl)ethyl)carbamate (d1); (e) subjecting (d1) with sodium hydride and methyl iodide in dry tetrahydrofuran to obtain benzyl (R)-(2-(cyclohex-1-en-1-yl)-2-(4-methoxyphenyl)ethyl)methyl)carbamate (e1); (f) epoxidizing (e1) by treating with metachloroperbenzoic acid in presence of sodium bicarbonate in dichloromethane under stirring at 25-35 degrees C for 1-3 hours to afford crude epoxide benzyl ((2R)-2-(7-oxabicyclo(4.1.0)heptan-1-yl)-2-(4-methoxyphenyl)ethyl)(methyl)carbamate (f1); and (g) subjecting the crude epoxide to selective epoxide opening and reduction in one pot using lithium aluminum hydride at reflux condition at 65-70 degrees C for 4-5 hours in tetrahydrofuran to afford (-)-venlafaxine.