Скопируйте ниже в модуль Worksheet и измените ячейку "A1":
Private Sub Worksheet_Change(ByVal Target As Range)
If Not (Intersect(Target, Range("A1")) Is Nothing) Then
i = i + 1
Worksheets("Sheet1").Cells(i, 2).Value = Worksheets("Sheet1").Cells(1, 1).Value
End If
End Sub