Erro de sintaxe - SQL

SELECT
  PRO.CODPROD,
  PRO.DESCRPROD,
  PRO.FABRICANTE,
  RESERVADO
FROM (
  SELECT SUM(EST.RESERVADO)
  FROM TGFEST EST
  WHERE EST.CODEMP = 1
) AS 'RESERVADO'
FROM
  TGFCAB CAB
  LEFT JOIN TGFPAR PAR ON CAB.CODPARC = PAR.CODPARC
  LEFT JOIN TGFITE ITE ON ITE.NUNOTA = CAB.NUNOTA
  LEFT JOIN TGFPRO PRO ON PRO.CODPROD = ITE.CODPROD
  LEFT JOIN TGFEST EST ON EST.CODPROD = PRO.CODPROD
WHERE
  EST.CODEMP = 1;