Chapter 13, Problem 13.39P

Interpretation Introduction

Interpretation:

A convergent synthesis, that might produce the same target as shown in Problem 13.38 in a higher yield, is to be constructed.

Concept introduction:

Synthesis may be designed by thinking in the reverse direction, from the product to the starting compound in a method called retrosynthesis. Retrosynthesis starts with the product and a suitable precursor from which it can be synthesized is determined, without considering specific reactions. The precursor must be a simpler molecule, which may or may not have a close structural relation to the target molecule. This process is repeated until an easily available (or easily prepared) precursor is reached. Each of these steps is called a transform. A synthesis is a specific sequence of chemical reactions that convert starting materials to the desired compound, called the target (or synthetic target).

For linear synthesis, the overall percent yield is equal to the product of the yields of the individual steps. In a convergent synthesis, portions of a target molecule are synthesized separately and are assembled together at a larger stage. In general, the yield of a multistep synthesis is higher if a target can be produced from a convergent synthesis instead of a linear one.