What is the meaning and use of "zu sollen"?

Question

Attempting to translate the following English into German:

You had him placed there deliberately so that Gloria would find him.

I said:

Du hattest ihn vorsätzlich hier hinstellen lassen, um Gloria ihn finden zu sollen.

But the German-speaking listener balked at

um Gloria ihn finden zu sollen

Looking in DWDS I do find zu sollen used:

Führen sie aber diesen Kampf im „Aus-Und“, um im Inneren Frankreichs siegen zu sollen, desto schlimmer!

Gärten oder Beete mit Trinkwasser bespritzen zu müssen, nur um erhöhte Gebühren bezahlen zu sollen, das ist wohl das stärkste, was an Gebührenschinderei geleistet werden kann.

What was wrong with my usage and when is this construction well used?

Answer 1

Um zu and its subjects

The main problem with your translation is that in German you can't change the subject (subject as a part of speech) in an "um zu" clause.

You can say

Ich habe ihn hier hinstellen lassen, um ihn schneller zu finden.

but you can't express with "um ... zu finden" that someone else should be able to find it. The subject of the main clause is automatically also the subject of the infinitive clause whenever you use "um zu".

If you wanted to express that, you would need to use an actual Nebensatz with "damit":

Ich habe ihn hier hinstellen lassen, damit Gloria ihn findet.

In English, you have the construction "I had it put there for Gloria to find it.", but that doesn't exist in German.

Read more here (in German): https://easy-deutsch.de/satzbau/nebensatz/finalsatz-damit-um-zu/

If you insist on using "um zu", you could use a different verb that allows the subject to stay the same, but that expresses the same thing semantically, like "lassen":

Ich habe ihn hier hinstellen lassen, um Gloria ihn finden zu lassen.
(I had it put here to let (or to have) Gloria find it.)

Note that "Gloria" is an accusative object of lassen here.

Um ... zu sollen

Moreover, because the subject of an "um zu" clause is the same as the one of the main clause, the expression "um zu ... sollen" makes no sense in most contexts. "Um zu" expresses an intent, "sollen" expresses an obligation. This doesn't fit together semantically, you normally don't do something in order to be obliged to do something, or, more literally, in order to "ought to" do something. It sounds just as strange as "in order to ought to" would sound in English.

Both examples from DWDS that you found for "um zu .. sollen" are quite unusual and not idiomatic. The first one doesn't make any sense to me and looks like a bad OCR scan, the second is (kind of) correct but unusual in that it is very implicit about the two acting subjects.

Gärten oder Beete mit Trinkwasser bespritzen zu müssen, nur um erhöhte Gebühren bezahlen zu sollen, das ist wohl das stärkste, was an Gebührenschinderei geleistet werden kann.

Here, the person that has to water the plants and the person that has to pay more fees are the same, that's why "um zu" can be used, but it is unusual in that the intent that "um zu" expresses is not the intent of that person, but of a different actor, namely the unnamed municipality (?) that imposes the sewer (?) fees and makes the plant watering laws.

Answer 2

The English original shows backshift.

He claims that he will get revenge.
He claimed that he would get revenge.

German doesn't have backshift in this context. There is a choice between indicative and Konjunktiv I or II, but it is independent of the tense of the main clause.

Er behauptet, dass er sich rächen wird/werde/würde.
Er behauptete, dass er sich rächen wird/werde/würde.

But note that, in other contexts (erlebte Rede), future werden becomes würde in order to indicate indirectness. For instance:

Besorgt dachte sie über ihre Zukunft nach.
Würde sie Erfolg haben? (corresponding to): "Werde ich Erfolg haben?"

Therefore, the following example is ambiguous. Either würde is used indicatively, to render future werde rächen, or as a subjunctive, to render present indicative räche.

Er behauptete, dass er sich bald rächen würde.
(corresponding to): "Ich werde mich bald rächen." or "Ich räche mich bald."

Returning to the sentence to be corrected: Since Gloria would find him is a finite clause, it requires damit, not um; also, future werden is not necessary (German frequently uses the present to talk about the future).

Du hast den da absichtlich hinstellen lassen,
damit Gloria ihn findet.

However,

damit Gloria ihn finden würde

is also possible, either understood as rendering an indicative with the subjunctive merely indicating indirectness, or as true subjunctive, i.e. saying that "finding" wouldn't happen without "placing" (irrealis mood).

Answer 3

Here, the construction is not correct with sollen. One would use lassen instead. The phrase is

jemand etwas finden lassen
(to let someone find something)

Used in the construction with um … zu, it would be as follows:

um Gloria ihn finden zu lassen
(to let Gloria find him)

Note, however, that this is not the verbatim translation of

so that Gloria would find him

The verbatim translation is

sodass Gloria ihn finden würde