for the following products
Fmoc-allo-Thr(But)-OH | Fmoc-allo-Thr(tBu)-OH | Fmoc-L-allo-Thr(tBu)-OH | N-alpha-(9-Fluorenylmethyloxycarbonyl)-O-tert-butyl-allo-L-threonine and (2S,3S)-2-((((9H-Fluoren-9-yl)methoxy)carbonyl)amino)-3-(tert-butoxy)butanoic acid