Voltage across open in this diode circuit with two batteries
For \$V_{D1}\$ you can consider two KVL loops—they should both give you the same answer. 

At point 1, you could start from the leftmost source (start from the ground) and say:

$$ \text{10V}-i_{D2}(10\text{k})-V_{D1}=0$$







simulate this circuit &ndash; Schematic created using CircuitLab

You already have the current then solving for \$V_{D1}\$ results in \$V_{D1}=-3.3\text{V}\$

You may also use another KVL loop:







simulate this circuit

$$ V_{D1}-i_{D2}(5\text{k})-(-10\text{V})=0$$

And solving for \$V_{D1}\$ will result in the same.