Manganates

recently i've been trying to figure out a good way to produce manganates.

one way is the tried and true method of using fused potassium hydroxide with manganese dioxide and an oxidizing agent, such as potassium chlorate. this of course works to oxidize the manganese.

i was thinking though, what about trying this in reverse? by reverse i mean reducing a permanganate, which is easier said than done when we're talking about reducing it to +6, as permanganates tend to reduce to manganese dioxide.

after awhile, i figured that if one were to add a fused alkali cation, the alkali would attack the permgananate at one of the doubly bonded oxygen atoms, causing the permanganate to reduce to manganate.

what do you think of the following reducing agents? LiAlH4, NaBH4, KOH, K2CO3