Transition metal compound, method for preparing the same, and catalyst composition comprising the same

A transition metal compound represented by Chemical Formula 1:

• wherein in Chemical Formula 1,
• M is a Group 4 transition metal,
• X1 and X2 are each independently hydrogen;
• halogen;
• or C1-20 alkyl;
• A is carbon or silicon,
• R11 and R12 are each independently hydrogen;
• halogen;
• C1-20 alkyl;
• C2-20 alkoxyalkyl;
• or C6-20 aryl;
• R21 is methyl,
• R22 is C3-20 alkoxyalkyl,
• R23 is unsubstituted C6-20 aryl;
• or C7-20 alkylaryl,
• R24 and R25 are each hydrogen;
• or R24 and R25 are connected with each other to form a C3-10 cycloalkane ring,
• R26 is C1-20 alkyl, and
• R27 is unsubstituted C6-20 aryl;
• or C7-20 alkylaryl.