(s,s)-2-phenyl-2-chloro-3,4-dimethyl-5-phenyl-[1,3,2]-oxazasilolidine;(4S,5S)-2-Chloro-3,4-dimethyl-2,5-phenyl-1-oxa-3-aza-2-silacyclopentane, min. 98% (~2:1 mixture of diastereomers);(4S,5S)-2-Chloro-3,4-dimethyl-2,5-diphenyl-1-oxa-3-aza-2-silacyclopentane