We have quite a successful site with high rankings on good keywords. Now the website is redesigned to a new one-page website. The keywords pointed to different pages from Google. What we've been thinking is to put a 301 redirect on all of the different pages (which score well in Google) to the new website (which has only one page).
My question is, as the links from Google might go to a slightly less relevant (less specific) page, will the rankings eventually drop or disappear? And is this duplicate content?
If you have other ideas to keep the rankings as much as possible, I'd love to hear them. I know it would be better to just keep similar pages on the new website, but the website is only one page and redesigning the full website is not an option.