Fmox: A Base‐Labile Aldehyde Protecting Group

Abstract A base‐labile aldehyde protecting group founded upon the 3‐Fmoc‐(1,3)‐oxazinane moiety has been developed. A series of novel or previously described acid‐labile aldehyde protecting groups were proven to be fully stable under the mild basic conditions, which completely removed the new base‐labile aldehyde protecting group. The possible reaction pathways for introducing and removing the different aldehyde protecting groups have been explored and characterized.