The present invention provides processes for making 2-((3R,5R,6S)-5-(3-chlorophenyl)-6-(4-chlorophenyl)-1-((S)-1-(isopropylsulfonyl)-3-methylbutan-2-yl)-3-methyl-2-oxopiperidin-3-yl)acetic acid as well as intermediates and processes for making the intermediates. Also provided are crystalline forms of the compound and the intermediates.