Catalyzed additions to alkene double bonds: (I) Fumarase-catalyzed hydration of alkene double bonds (II) Alumina-catalyzed hydrochlorination of alkene double bonds

The stereospecific hydration of (5)-malate to fumarate, catalyzed by fumarase, was extensively analyzed by NMR. The NMR techniques employed were one dimensional 2H and NOE Difference, and two dimensional ^^H COSY. Various potentional substrates were tried for fumarase-promoted hydration with no sucesss. It was concluded that mesaconate is possibly the largest molecule that can fit into the active site of fumarase in the correct orientation for hydration to occur. Thionyl chloride and appropriately prepared alumina was found to promote the addition of HC1 to norbornadiene ( I ), resulting in71%(+l%) exo-5-chloronorbornene ( II ) and 29% 3-chloronortricyclene ( HI ) at room temperature, while lower temperatures favor the synthesis of the kinetic product, HI. Oxalyl chloride and alumina also produces II and HI, but the product composition slowly equilbrates mostly to the thermodynamic product, HI. Treatment of alumina with deuterium oxide was found to promote the addition of DC1 to norbornadiene, when used with thionyl chloride, to give 1 8% exo,aft'-5-chlorobicyclo[2.2.1]hept-2-ene-7-d ( VHIa ), 33% exo,exo-6-chlorobicyclo[2.2.1]hept-2-ene-5-d ( VHIb ), 21% 5-chlorotricyclo[2.2. 1 .0^2,6]heptane-3-d ( VEHc ), 20% H, and 8% HI. A higher ratio of Vmb/Vma for the catalyzed DC1 addition than for the uncatalyzed addition1 suggests that the 1 ,2-addition, when using alumina, gives a somwhat higher proportion of syn-addition.