Herein we describe the first organocatalytic asymmetric C(sp2)−H allylation of racemic trisubstituted allenoates with Morita–Baylis–Hillman (MBH) carbonates to access axially chiral tetrasubstituted allenoates. Various trisubstituted allenoates and MBH carbonates were well tolerated under mild reaction conditions, providing novel chiral tetrasubstituted allenoates with adjacent axial chirality and tertiary carbon stereocenters in high yields with good to excellent diastereoselectivities and enantioselectivities.
The δ-sulfonamido-substituted enones were employed as phosphine acceptor in phosphine-catalyzed (4 + 2) annulation of 1,1-dicyanoalkenes. They served as a four-membered synthon to react with 1,1-dicyanoalkenes under mild reaction conditions, producing piperidine derivatives in moderate to excellent yields with good to excellent diastereoselectivities.
An efficient K 2 CO 3 -catalyzed 1,4-addition/intramolecular cyclization/aromatization reaction of aurone-derived 1azadienes with trisubstituted allenoates has been developed, giving a series of benzofuro [3,2-b]pyridines in moderate to excellent yields. The reaction proceeded efficiently under an air atmosphere without the use of transition metal catalysts. This protocol provides a concise approach to benzofuro[3,2-b]pyridines.
In this paper, we designed and synthesized a new type of cyclic carbonates, allenylethylene carbonates (AECs). With AECs as reactive precursors, we developed palladium-catalyzed (3+3) annulation of AECs with nitrile oxides. Various AECs worked well in this reaction under mild reaction conditions. A variety of 5,6-dihydro-1,4,2-dioxazine derivatives with allenyl quaternary stereocenters can be accessed in a facile manner in high yields (≤98%).
In this paper, an asymmetric allylic alkylation of easily available azomethine ylides with Morita−Baylis−Hillman (MBH) Carbonates through a copper (I) / Lewis base cooperative catalysis strategy has been realized. The...
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