合成路线1

The hydrolysis of methyl (2E, 4E)-hexadecadienoate (I) with KOH in THF gives the corresponding free acid (II), which is treated with (COCl)2 in dichloromethane to yield the acid chloride (III). The esterification of (III) with trichloroethanol (IV), TEA and DMAP affords the trichloroethyl ester (V), which is stereospecifically dihydroxylated by means of AD-mix-alpha, methanesulfonamide and NaHCO3 in t-butanol/water to provide the dihydroxyester (VI). The reaction of (VI) with SOCl2 in refluxing CCl4 gives the cyclic sulfite (VII), which is alkylated by means of CuCN, Li-C6H13 and BF3/Et2O in THF to give 5(S)-hydroxy-2(S)-hexyl-3(E)-hexadecanoic acid trichloroethyl ester (VIII). The cleavage of the ester group of (VIII) by means of Zn/AcOH yields the corresponding free acid (IX), which is submitted to cyclization by reaction with Br2 in CCl4/MeOH in the presence of NaHCO3 to afford the brominated beta lactone (X). Radical debromination of (X) by means of di-tert-butyl peroxide (DBPO), Ph2Se2, and Bu3SnH in toluene provides the beta lactone (XI), which is condensed with N-(benzyloxycarbonyl)-L-leucine (XII) by means of DCC and DMAP in dichloromethane to furnish the ester (XIII). The cleavage of the Boc group of (XIII) by means of H2 over Pd/C in THF gives the free amino acid ester (XIV), which is finally N-formylated by means of acetic formic anhydride (XV) in ethyl ether to yield the target tetrahydrolipstatin.