They looked into the possibility in the 1930s. I just wrote briefly about the possibility of expulsion to Madagascar which was entertained by the Nazis, but it was not the only option investigated, and Palestine was another one that was floated.

In fact, it should be noted, that between 1933 and 1939, over 50,000 German Jews left Germany for Palestine with the encouragement of the Nazi government. The Haavara Transfer Agreement was signed on August 27, 1933, which allowed Jews who left for Palestine to keep considerably more of their wealth than Jews who left Germany for other destinations (The Reich Flight Tax was very, very high).

This was a simply convenient arrangement though, nothing more. Germans got what they wanted - more Jews out of Germany - and Zionists got what they wanted - more Jewish immigration to Palestine. Increasing emigration was investigated by Adolf Eichmann of the SD, who made contacts with Zionists and even visited Palestine, but more and more, there was concern that allowing Jews to build up their presence there, with their aim of an eventual Jewish state, was a threat to Germany, so by the late 1930s, the idea was pretty much a dead one. As noted in the linked answer, Madagascar again became a possibility in 1940, but by that point, it wasn't simply an idea of "get out, bye, have a nice life" but one giant concentration camp. Siberia would also be suggested, a nice, frozen wasteland where the Jews could freeze to death. Either way, it wasn't simply about forcing emigration but forcible deportation and confinement, and deportation to a British held territory was out of the question once war broke out. Instead, deportation eastward became the aim.

Evans' "T Third Reich in Power" and Kershaw's "Hitler: 1936-1945"