Look at the given synthesis and the provided reagents. Fill in the blanks with the single letter code of the appropriate reagent, or the appropriate descriptive vocabulary word/phrase to complete the description. Remember the computer is very literal so check your spelling carefully. First we add reagent to form the anion, then add reagent to act as an electrophile for a mechanism. Then we add reagent followed by reagent to give the product with regioselectivity. The initial product of this reaction series contain a(n) functional group which rearranges to the final product via a mechanism. If instead we wanted to form 2-pentanone we’d use reagent in the last step to add the oxygen with regioselectivity.