a) What is the product in the following reaction? excess NaBH,/CH,OH OH OH "OH II III OH OH OH "OH IV V III | 0000 II IV V b) What is product E for the following reaction sequence? PBrz Mg . H H H2O PCC -OH A B C D E ether CH2Cl2 H OH I II III IV0 V IV OOOOO = = => a) What is product E for the following reaction sequence? of 1. CH3CH2CH2MgBr/ether 2. H2O OH oforon IV none of these IV