5,5-Dimethylthiazolidine-4-carboxylic acid (I) is protected as the N-Boc derivative (II), and subsequently treated with allyl bromide (III) and triethylamine to form the allyl ester (IV). Acidic Boc group cleavage in (IV) provides amino ester (V), which is further coupled to the lactone acid (VI) to furnish amide (VII). The allyl ester group of (VII) is then removed by treatment with morpholine and Pd(PPh3)4, yielding acid (VIII). This is then coupled to (3,5-dimethylisothiazol-4-yl)methyl amine (IX) employing EDC/HOAt to afford the corresponding amide (X). Lactone ring opening in (X) by hydrolysis with LiOH gives rise to the hydroxy acid (XI), which is further protected as the silyl ether (XII) employing t-butyldimethylsilyl triflate.

Coupling of acid (XII) with (S,S)-4-aminochroman-3-ol (XIII) in the presence of HBTU provides amide (XIV). Finally, desilylation of (XIV) with tetrabutylammonium fluoride gives rise to the target compound.