Powershell syntax error?

Hi,

why is that inside powershell I can run command:

ls ~\Downloads | where {($_.LastWriteTime).AddDays(1) -lt (get-date)} | remove-item -force -recurse

But when I try to run this in CMD shell:

powershell -command {ls ~\Downloads | where {($_.LastWriteTime).AddDays(1) -lt (get-date)} | remove-item -force -recurse}

Command fails.