Given a sample of (R) -2,3-dimethylhexan-3-ol, which of the following would be the best synthesis of (R) -3-chloro-2,3-dimethylhexane?

A) HCl/ZnCl₂
B) PCl₃
C) SOCl₂
D) 1. TsCl/Pyridine
2) NaCl
E) none of the above

The best way to prepare (R)-3-chloro-2,3-dimethylhexane is through the use of thionyl chloride (SOCl2). This reagent will convert the alcohol group on (R)-2,3-dimethylhexan-3-ol to a chloride group while also providing the necessary inversion of configuration to get the (R) enantiomer of the product. Option A, HCl/ZnCl2, may lead to racemization of the starting material. Option B, PCl3, may lead to a mixture of both enantiomers of the product. Option D, TsCl/Pyridine and NaCl, will convert the alcohol group to a tosylate group, which is a good leaving group, but it will not invert the configuration, so the resulting product will be the (S) enantiomer.