Intramolecular Nozaki–Hiyama–Kishi reactions and Ln(III)-catalyzed allylic rearrangement as the key steps towards 10-membered ring enediynes
摘要:
A general and facile synthesis of the 3-substituted 10-membered ring enediynes 18-22 from the aldehydes 8 and 15 has been established by utilizing the intramolecular Nozaki-Hiyama-Kishi reaction and the lwanthanide(III)-catalyzed rearrangement of allylic alkoxyacetates as the key steps. This work provides ready access to the (E)-3-acyloxy-4-(arylmethylidene)cyclodeca-1,5-diynes, which can be converted into the bioactive enediynes under physiological conditions. (C) 2001 Elsevier Science Ltd. All rights reserved.
Intramolecular Nozaki–Hiyama–Kishi reactions and Ln(III)-catalyzed allylic rearrangement as the key steps towards 10-membered ring enediynes
摘要:
A general and facile synthesis of the 3-substituted 10-membered ring enediynes 18-22 from the aldehydes 8 and 15 has been established by utilizing the intramolecular Nozaki-Hiyama-Kishi reaction and the lwanthanide(III)-catalyzed rearrangement of allylic alkoxyacetates as the key steps. This work provides ready access to the (E)-3-acyloxy-4-(arylmethylidene)cyclodeca-1,5-diynes, which can be converted into the bioactive enediynes under physiological conditions. (C) 2001 Elsevier Science Ltd. All rights reserved.
Cascade cyclization of bromoenynes bearing an aryl group with catalytic amounts of palladium(II) acetate and cesium carbonate led to the direct construction of tri- or tetracyclic heterocycles. Direct arylation of a pyrrole, furan or thiophene ring in the cascade reaction affords the corresponding fused heteroarenes in moderate to good yields. tandem reaction - palladium - polycycles - fused-ring systems
A Novel and Convenient Protocol for Synthesis of α-Haloacrylates
作者:Biao Jiang、Ying Dou、Xiangya Xu、Min Xu
DOI:10.1021/ol702859y
日期:2008.2.1
A.novel and convenient protocol for synthesis of alpha-haloacrylates starting from phosphonium ylide and aldedyde or alcohol was described. Halodimethylsulfonium halide was used for the first time in halogenation of phosphonium ylide. Good yield as well as a high Z/E ratio were shown in representative cases, and an umpolung dimethyl sulfide-ylide species might be involved as an intermediate.