The palladium‐catalyzed asymmetric [4+3] cyclization of trimethylenemethane donors with benzofuran‐derived azadienes furnishes chiral benzofuro[3,2‐b]azepine frameworks in high yields (up to 98 %) with exclusive regioselectivities and excellent stereoselectivities (up to >20:1 d.r., >99 % ee). This catalytic asymmetric [4+3] cyclization of Pd‐trimethylenemethane can enrich the arsenal of Pd‐TMM reactions in organic synthesis. In addition, this strategy provides an alternative approach to chiral azepines by a transition‐metal‐catalyzed asymmetric [4+3] cyclization.

No abstract

The palladium‐catalyzed asymmetric [4+3] cyclization of trimethylenemethane donors with benzofuran‐derived azadienes furnishes chiral benzofuro[3,2‐b]azepine frameworks in high yields (up to 98 %) with exclusive regioselectivities and excellent stereoselectivities (up to >20:1 d.r., >99 % ee). This catalytic asymmetric [4+3] cyclization of Pd‐trimethylenemethane can enrich the arsenal of Pd‐TMM reactions in organic synthesis. In addition, this strategy provides an alternative approach to chiral azepines by a transition‐metal‐catalyzed asymmetric [4+3] cyclization.

A series of 2,4-disustituted 1,2,4-triazole-3-ones 4 were prepared via the Iodine-DMSO-promoted three-component reaction of formaldehyde, amines and hydrazines in moderate yields.

of main observation and conclusion A palladium-catalyzed asymmetric [4 + 3] cycloaddition of trimethylenemethanes and indoline-derived aza-dienes has been developed. The potential [3 + 2] side pathway was completely suppressed in the process. This protocol provides an efficient access to azepino[2,3-b]indoles bearing two vicinal stereocenters in generally excellent diastereo-and enantioselectivities (up to > 20 : 1 dr, 99% ee).