Following is the structure of immunosuppressant FK-506, a molecule shown to disrupt calc...

Following is the structure of immunosuppressant FK-506, a molecule shown to disrupt calcineurinmediated signal transduction in T-lymphocytes.

(a) There are three carbon–carbon double bonds present in this molecule. Which of the three has the potential for cis/trans isomerism? Assign a cis or trans configuration to each carbon–carbon double bond that has this possibility.

(b) How many stereocenters are present in this molecule? How many stereoisomers are possible for it?

(c) Are there any aromatic components in this molecule?

(d) Consider the two carbon atoms marked with asterisks. Determine the absolute (R or S) configuration of each stereocenter.

(e) Because of the presence of a 21-member ring, this molecule is described as a macrocycle. This ring is fashioned by three types of bonds, several carbon–carbon bonds, one ester, one hemiacetal, and one amide. Locate the ester and the hemiacetal.

(f ) Draw the structural formula of the long chain compound that would result if the hemiacetal were to cleave to an alcohol and a carbonyl compound.