(2S,2'S,3S,3'S)-3,3'-Di-tert-butyl-4,4'-bis(2,6-dimethoxyphenyl)-2,2',3,3'-tetrahydro-2,2'-bibenzo[d][1,3]oxaphosphole, 97% (>99% ee) (2S,2'S,3S,3'S)-Bis-BIDIME