Enantioselective Synthesis of 3,4-Disubstituted <i>cis</i>- and <i>trans</i>-1,2,5-Thiadiazolidine-1,1-dioxides as Precursors for Chiral 1,2-Diamines Christian Schüttler Zhen Li-Böhmer Klaus Harms Paultheo von Zezschwitz 10.1021/ol3034753.s002 https://acs.figshare.com/articles/journal_contribution/Enantioselective_Synthesis_of_3_4_Disubstituted_i_cis_i_and_i_trans_i_1_2_5_Thiadiazolidine_1_1_dioxides_as_Precursors_for_Chiral_1_2_Diamines/2442958 Both, <i>cis</i>- and <i>trans</i>-3,4-disubstituted thiadiazolidines <b>5</b> and <b>6</b> can enantioselectively be obtained from thiadiazoles <b>2</b> which, in turn, are efficiently prepared from the respective 1,2-diketone by an improved protocol. An asymmetric ruthenium-catalyzed transfer hydrogenation followed by a diastereoselective hydride addition furnishes exclusively the <i>cis</i>-isomers <b>5</b> which, under acidic conditions, undergo a novel isomerization into the <i>trans</i>-isomers <b>6</b>. These cyclic sulfamides can be transformed into 1,2-diamines as well as 2,3-diamino acids. 2013-02-15 00:00:00 enantioselectively diamino thiadiazoles 2 6. diastereoselective hydride addition hydrogenation transfer acidic conditions diketone DiaminesBoth Chiral Precursor diamine Disubstituted cyclic sulfamides thiadiazolidine tran Enantioselective Synthesis novel isomerization