@P04740@ in which a @T06246@ is formed. However, @P04740@ in which @S05983@ present in the @M04017@ is merely retained in the @P04735@ is not to be regarded as @S05994@. For example, the @P04740@ of a @C01057@ @M04017@, e.g. d-propylene oxide (d-methyloxirane), with retention of @C01249@ is not considered to be a stereospecific reaction; however, selective @P04740@, with retention, of one of the @E02069@ present in a mixture of d- and l-propylene oxide molecules is so classified.
Purple Book, 1st ed., p. 19 [Terms] [Book]