The solution in the Laplace Domain, with zero initial conditions, requires to solve the circuit simply replacing the inductors impedance effect \$v(t)=L\frac{di(t)}{dt}\$ with \$V(s)=sLI(s)\$
The circuits expressions are:
$$V_1=R_1I_1+sL_1(I_1-I_2)$$
$$sL_1(_I1-I_2)=R_2I_2+sL_2I_2$$$$sL_1(I_1-I_2)=R_2I_2+sL_2I_2$$
$$V_2=sL_2I_2$$
They can be simply rearranged as:
$$I_1=(V_1+sL_1I_2)/(R_1+sL_1)$$$$I_1={V_1+sL_1I_2 \over R_1+sL_1}$$
$$I_2=sL_1I_1/(R_2+sL_2+sL_1)$$$$I_2={sL_1I_1 \over R_2+sL_2+sL_1}$$
From here, I_1\$I_1\$ and I_2\$I_2\$ can be obtained:
$$I_2=V_1sL_1/((R_1+sL_1).(R_2+sL_2+sL_1)-(sL_1)^2)$$$$I_2={V_1sL_1 \over R_1+sL_1}{1 \over (R_2+sL_2+sL_1)-(sL_1)^2}$$
$$I_1={V_1\over (R_1+sL_1)}(1+(sL_1)^2/((R_1+sL_1).(R_2+sL_2+sL_1)-(sL_1)^2))$$$$I_1={V_1\over R_1+sL_1}{1+(sL_1)^2 \over (R_1+sL_1)((R_2+sL_2+sL_1)-(sL_1)^2)}$$
And finally, the transfer function is calculated as:
$$V_2/V_1=1-R_1I_1/V_1-R_2I_2/V_1$$