A Stepwise Annulation for the Transformation of Cyclic Ketones to Fused 6 and 7-Membered Cyclic Enimines and Enones

The efficient construction of functionalized polycyclic structures is an imports nt objective in organic synthesis.Herein,we disclose a three-step"[2+n]"annulation method for the transformation of cyclic ketones to fused enimines and enones.The method relies on the Suzuki coupling reaction and the amide reductive alkenylation reaction.A series of fused bicyclic(6/6,6/7,8/7)and tricyclic(6/6/6;6/6/7,6/5/7)ring systems bearing an α,β-enimine or an α,β-enone functionality have been synthetized in good overall yields.

Ni-catalyzed direct alcoholysis of N-acylpyrrole-type tertiary amides under mild conditions

N-Acylpyrrole-type amides are a class of versatile building blocks in asymmetric synthesis.We report that by employing Ni(COD)2/2,2′-bipyridine(5 mol%)catalytic system,the direct,catalytic alcoholysis of N-acylpyrrole-type aromatic and aliphatic amides with both primary and secondary alcohols can be achieved efficiently under very mild conditions(rt,1 h)even at gram scale.By increasing the catalyst loading to 10 mol%,prolonging reaction time(18 h),and/or elevating reaction temperature to 50°C/80°C,the reaction could be extended to both complex and hindered N-acylpyrroles as well as to N-acylpyrazoles,Nacylindoles,and to other(functionalized)primary and secondary alcohols.In all cases,only 1.5 equiv.of alcohol were used.The value of the method has been demonstrated by the racemization-free,catalytic alcoholysis of chiral amides yielded from other asymmetric methodologies.