This problem is an introduction to the planning of multistep syntheses.
For use, you have six reactant compound (A through F), and eight reagents (1 through 8), shown below.
Following these lists, five multistep syntheses are outlined. For each of these, certain reactants or reagents must be identified by writing an appropriate letter or number in designated answer boxes. Write a single letter or number, indicating your choice of the best reactant, in each answer box.
(1) Jones' reagent `[Na_(2)Cr_(2)O_(7)` in `H_(3)O^(+)]`, (2) `PC C [CrO_(3)` in pyridine `+ HCl]`
(3) Sodium hydride `NaH`, (4) Sodium borohydride `NaBH_(4)`
(5) Thionyl chloride `SOCl_(2)`, (6) Phosphorus tribromide `PBr_(3)`
(7) Aluminium trichloride `AlCl_(3)`, (8) Magnesium turnings in ether
