Efficient <i>trans</i>-Selectivity in the Cyclocondensation of (<i>S</i>)-2-[2-(<i>p</i>-Tolylsulfinyl)phenyl]acetaldehyde with Activated Dienes Catalyzed by Yb(OTf)<sub>3</sub> José L. García Ruano M. Ángeles Fernández-Ibáñez M. Carmen Maestro 10.1021/jo061128n.s003 https://acs.figshare.com/articles/journal_contribution/Efficient_i_trans_i_Selectivity_in_the_Cyclocondensation_of_i_S_i_2_2_i_p_i_Tolylsulfinyl_phenyl_acetaldehyde_with_Activated_Dienes_Catalyzed_by_Yb_OTf_sub_3_sub_/3056794 Reactions of (<i>S</i>)-2-[2-(<i>p</i>-tolylsulfinyl)phenyl]acetaldehyde <b>1 </b>with Danishefsky's and related dienes took place in the presence of Yb(OTf)<sub>3</sub> in a completely stereoselective manner, mediated by a remote sulfinyl group (1,5-asymmetric induction), to afford the corresponding 2,3-dihydro-4<i>H</i>-pyran-4-ones. These reactions followed a stepwise mechanism, as was corroborated by isolation of the corresponding intermediates, with a high level of <i>trans</i>-selectivity for 4-methyl-substituted dienes. Treatment of the adducts with Raney Ni provided concomitant cleavage of the C−S bond and reduction of the conjugated carbonyl grouping. 2006-09-29 00:00:00 adduct carbonyl grouping presence Efficient diene Raney Ni sulfinyl Activated Dienes Catalyzed Yb mechanism intermediate induction Cyclocondensation stereoselective manner Danishefsky isolation cleavage bond dihydro