(11aR)‐(+)‐10,11,12,13‐Tetrahydro‐5‐phenoxydiindeno[7,1‐de:1′,7′‐fg][1,3,2]dioxaphosphocin and (11aS)‐(−)‐10,11,12,13‐Tetrahydro‐5‐phenoxydiindeno[7,1‐de:1′,7′‐fg][1,3,2]dioxaphosphocin