Which is more more stable, cis - or trans- 1,3-di-(methylcarboxylate) cyclobutane?

Explanation

To determine which is more stable between cis- and trans-1,3-dimethylcarboxylate cyclobutane, we will analyze the structures and steric interactions of both isomers.

### Step-by-Step Solution:

1. **Draw the Structures**:
- For **cis-1,3-dimethylcarboxylate cyclobutane**, both methyl carboxylate groups (MeOOC) are on the same side of the cyclobutane ring. This means that both groups will occupy equatorial positions when possible.
- For **trans-1,3-dimethylcarboxylate cyclobutane**, the methyl carboxylate groups are on opposite sides of the ring. This results in one group being axial and the other being equatorial.

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