I've written in the past about Hitler and the US. Hitler was not aware in advance of the plan, but as I note in this and this answer+follow-ups, Japan was viewed by Hitler as something of a 'force equalizer' to balance out the threat posed by American naval power, and this played a large influence in his decision to declare war on the US, something which had been up to then resisted despite calls for it from certain corners in Germany.

Hi there,

On /r/AskHistorians we often get questions along the lines of 'what did Hitler think about X' - I mean, as an April Fools joke one year, we changed the sub to /r/AskAboutHitler. However, for better or worse, many of these questions about what Hitler thought are, in the literal sense, unanswerable. We don't know what Hitler thought about many things, and especially about things which were inconsequential for him. Hitler did not keep a diary, and the collections of his private conversations is disjointed and nowhere near complete, being almost completely dependent on the post-war recollection of his intimates (who may also be unreliable in their recollections, especially given those circumstances).

Of course, you may still get an answer to this particular question! However, broadly speaking, proving the negative is very hard (there could be an 1965 article on the topic in Swahili), and if you've asked a question which is almost certainly "We don't know, and he probably didn't care anyways", few historians familiar with the topic matter actually are going to want to put in the necessary gruntwork, doubly so about a man who on a personal level was decidedly uninteresting.

For more information that will be helpful in understanding the context around your question, please read /u/commiespaceinvader's wonderful post on why Hitler's opinions actually aren't that interesting, and please see here for an example of a historian attempting to find evidence about Hitler's thoughts on a topic, but finding that it is likely unanswerable.