The structures for 12 and 13 in the published Scheme 4 were inadvertently drawn incorrectly, with the methyl and cyclohexyl groups transposed in the original structures.
The corrected Scheme 4 appears below.
The structures for 12 and 13 in the published Scheme 4 were inadvertently drawn incorrectly, with the methyl and cyclohexyl groups transposed in the original structures.
The corrected Scheme 4 appears below.