une possibilité
Private Sub CommandButton1_Click()
Dim Tableau As Variant
Dim derlgn As Long
With Worksheets('Feuil1')
derlgn = .Range('B65536').End(xlUp).Row
For L = 3 To derlgn
Tableau = Split(.Cells(L, 2).Value, Chr(32))
.Cells(L, 4).Resize(1, UBound(Tableau, 1) + 1) = Tableau
Next
End With
End Sub