Organocatalytic process for asymmetric synthesis of decanolides

An organo catalytic process for the preparation of decanolides of Formula Ic

• wherein the said process comprising the steps of:
• i) allylboration of aldehyde (1)
• in presence of allyldiisopinocamphenylborane at temperature in the range of −120° C. to −80° C. for 1-2 hours in non-polar organic solvents selected from the group consisting of diethyl ether, pentane, cyclopentane, benzene, toluene, 1,4-dioxane, chloroform, and mixtures thereof followed by treatment with NaOH and aqueous H2O2 to obtain chiral allylic alcohol (3)
• ii) esterification of allylic alcohol (3) with butyldimethylsilyl(TBS) protected carboxylic acid (15)
• in presence of N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride, 4-dimethylaminopyridine in DCM at temperature range 0° to 30° C. for 5 to 8 hours with subsequent deprotection of TBS in presence of tetra-n-butylammonium fluoride in THF for 6-8 hours yields allylic alcohol (17)
• and
• iii) ring closing metathesis reaction of compound (17) in presence of Grubbs II catalyst (5 to 15%) in dry CH2Cl2 for 18-24 hours to obtain decanolides of Formula Ic.