hi all,
sorry for the long absence but in this period i have to work a lot in the lab.
So at the and i found the my LiAlH4 was ,in some way, bad....maybe becouse it wasen't conserved very well so it don't react very well.
I found this becouse we prove another reduction that in the past function, with the same LiAlH4 and the reaction don't start.
So this is the problem...thank to all for the answare