Question

Notice that there are actually 3 chiral centers in the (1S)-[endo]-(-)borneol substrate. C1 and C2 are obvious. What is the other center? Is the absolute configuration at this center R or S?

Answer 1

The third chiral center in (1S)-[endo]-(-)borneol, apart from C1 and C2, is C4. The absolute configuration (R or S) can be determined by prioritizing substituents and applying Cahn-Ingold-Prelog rules, which require visualizing the substituents' arrangement around the chiral center.

Step-by-step explanation:

In (1S)-[endo]-(-)borneol, the additional chiral center besides C1 and C2 is C4. The absolute configuration at this center can be determined by the prioritization of substituents and application of the Cahn-Ingold-Prelog rules. You need to look at the particular molecule, prioritize the substituents attached to the chiral center from highest to lowest according to atomic number, and then visualize or draw the molecule to determine if the sequence is clockwise (R) or counterclockwise (S). Since I cannot see your specific molecule, I can't accurately determine the absolute configuration for C4, but this is the methodology you would use.

Answer 2

C5 and its absolute configuration is R

Step-by-step explanation:

A chiral center is a carbon atom (C) which is bonded to four different groups, generating optical activity in the molecule.

The first two chiral centers are:

• C1: bonded to OH, H, the carbon chain (seen from left to right) and the carbon chain (seen fron rigth to left).
• C2: bonded to CH3, the above C and its CH3, the carbon chain (seen from left to right) and the carbon chain (seen fron rigth to left).

The thrid chiral center is C5, which is bonded to H, the above C and its CH3, the carbon chain (seen from left to right) and the carbon chain (seen fron rigth to left).

The absolute configuration of it is R (clockwise)