Gold(III) Porphyrin-Catalyzed Cycloisomerization of Allenones
摘要:
Gold(III) porphyrin-catalyzed cycloisomerization of allenones gave the corresponding furans in good to excellent yields (up to 98%) and with quantitative substrate conversions. By recovering the Au(III) catalyst, a recyclable catalytic system is developed with over 8300 product turnovers attained for the cycloisomerization of 1-phenyl-buta-2,3-dien-1-one. The versatility of the gold(Ill) porphyrin catalyst was exemplified by its application to the hydroamination and hydration of phenylacetylene in 73% and 87% yield, respectively.
Isomerizations on silica gel: Synthesis of allenyl ketones and the first Nazarov cyclizations of vinyl allenyl ketones
作者:A Stephen、K Hashmi、Jan W Bats、Ji-Hyun Choi、Lothar Schwarz
DOI:10.1016/s0040-4039(98)01619-0
日期:1998.10
chromatographic workup of crude, terminal propargyl ketones 5 on silica gel directly leads to terminal allenylketones 6. When the other substituent on 5 was electron-rich, 7 was observed as side-product. If the other substituent on 5 was electron-poor, the isomeric 1-propynyl ketone 8 was the side-product. Chromatography of the crude propargyl vinyl ketones 10 on silica gel delivers the products of a Nazarov