There was this rule of alkene reactions that says:
Syn reaction + cis alkene gives Meso Product (if same groups on both carbons of the alkenes)
Cis + anti or trans + syn gives two enantiomers
anti reaction + trans alkene gives meso (if same groups on both carbon of alkene).
This topic is confusing to many students, first of all, what if the two groups on the carbons weren't the same, for instance in this reaction in the picture, it's a trans alkene with anti reaction, I would like a rule that would spare me from using models, according to my rule stated above, it should give meso (but groups aren't the same on both sides) so it should give R/S? or S/R? Hence two enantiomers? like is my logic correct, since it's an anti reaction, both carbons on the double bond need DIFFERENT configurations, and if it's a syn reaction, they should have SAME configuration?