Trispiro(furan-3(2H),2'(5'H)-furan-5',8''-(8H-4,8a)propano(1H-2)benzopyran-7''(3''H),2'''-oxiran)-3''-one, 5''-(acetyloxy)-3',4',4'',4''a,5'',6''-hexahydro-4''-methyl-, (4''S-(4''alpha,4''aalpha,5''beta,7''beta,8''alpha(S*),8''aalpha))-