Download full text in PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... Acyclic stereoselection. Erythroselective aldol condensation of 4-acyl-2,3-dihydro-4h-1,4-benzothiazine and 10-acylphenothiazine. ... The title amides undergo aldol-type cross-condensation providing aldols of exclusive erythro configuration. The preferred cis geometry of the precursor ...