Mercury(II)-Catalyzed Synthesis of Spiro[4.5]decatrienediones from Allenyl Ketones and Comparison with Silver(I)-, Palladium(II)- and Brønsted Acid-Catalyzed Reactions
摘要:
The allenyl p-methoxybenzyl ketone 3a and allenyl p-siloxybenzyl ketones 6b selectively delivered three different products with three different transition metal-catalysts. With Hg(II)-catalysts a spiro[4.5]decene 9, with Ag(I)-catalysts a 2-substituted furan (10/11) and with Pd(II)-catalysts a 2,4-disubstituted furan (8/12) was formed. Only with perchloric acid the intermolecular addition of water to the allene, leading to 1,3-dicarbonyl compounds 7, was observed. While with the corresponding allenyl o-methoxybenzyl ketone 3b the Ag(I)- and Pd(II)-catalysts provided the expected products, the mercury-catalyst led to a new and interesting side-product rac-17 which combined both the furan moiety and the spiro[4.5]decene moiety. Efforts to prepare allenyl hydroxybenzyl ketones failed, in one case a small amount of a 5H-benzo[b]oxepin-4-one 21 was isolated. It also was not possible to extend the spirocyclization to allenyl p-siloxyphenyl ketone 6a or allenyl 2-(p-siloxyphenyl)ethyl ketone 6c.
Mercury(II)-Catalyzed Synthesis of Spiro[4.5]decatrienediones from Allenyl Ketones and Comparison with Silver(I)-, Palladium(II)- and Brønsted Acid-Catalyzed Reactions
摘要:
The allenyl p-methoxybenzyl ketone 3a and allenyl p-siloxybenzyl ketones 6b selectively delivered three different products with three different transition metal-catalysts. With Hg(II)-catalysts a spiro[4.5]decene 9, with Ag(I)-catalysts a 2-substituted furan (10/11) and with Pd(II)-catalysts a 2,4-disubstituted furan (8/12) was formed. Only with perchloric acid the intermolecular addition of water to the allene, leading to 1,3-dicarbonyl compounds 7, was observed. While with the corresponding allenyl o-methoxybenzyl ketone 3b the Ag(I)- and Pd(II)-catalysts provided the expected products, the mercury-catalyst led to a new and interesting side-product rac-17 which combined both the furan moiety and the spiro[4.5]decene moiety. Efforts to prepare allenyl hydroxybenzyl ketones failed, in one case a small amount of a 5H-benzo[b]oxepin-4-one 21 was isolated. It also was not possible to extend the spirocyclization to allenyl p-siloxyphenyl ketone 6a or allenyl 2-(p-siloxyphenyl)ethyl ketone 6c.
Studies on the Himbert Intramolecular Arene/Allene Diels–Alder Cycloaddition. Mechanistic Studies and Expansion of Scope to All-Carbon Tethers
作者:Yvonne Schmidt、Jonathan K. Lam、Hung V. Pham、K. N. Houk、Christopher D. Vanderwal
DOI:10.1021/ja4025963
日期:2013.5.15
The unusual intramolecular arene/allene cycloaddition described 30 years ago by Himbert permits rapid access to strained polycyclic compounds that offer great potential for the synthesis of complex scaffolds. To more fully understand the mechanism of this cycloaddition reaction, and to guide efforts to extend its scope to new substrates, quantum mechanical computational methods were employed in concert
Mercury(II)-catalyzed synthesis of spiro[4.5]decatrienediones in the presence of water
作者:A.Stephen K. Hashmi、Lothar Schwarz、Michael Bolte
DOI:10.1016/s0040-4039(98)02057-7
日期:1998.12
Treatment of the easily available p-methoxybenzyl allenyl ketone 2 or the (p-tert-butyldimethylsiloxybenzyl) allenyl ketone 9 with 1% Hg(ClO4)(2) in acetonitrile/water provided good yields of the spiro[4.5]deca-3,5,9-triene-2,8-dione 6c. The Hg(II)-catalyzed addition of water to the allene was much slower, the 1,3-diketone 7 was only a minor side-product. The isomeric a-methoxybenzyl allenyl ketone 12 formed some spiro[4.5]deca-3,7,9-triene-2,6-dione 13, the side-reactions were the addition of water and a new spirocyclization/dimerization leading to 15. (C) 1998 Elsevier Science Ltd. All rights reserved.
Mercury(II)-Catalyzed Synthesis of Spiro[4.5]decatrienediones from Allenyl Ketones and Comparison with Silver(I)-, Palladium(II)- and Brønsted Acid-Catalyzed Reactions
The allenyl p-methoxybenzyl ketone 3a and allenyl p-siloxybenzyl ketones 6b selectively delivered three different products with three different transition metal-catalysts. With Hg(II)-catalysts a spiro[4.5]decene 9, with Ag(I)-catalysts a 2-substituted furan (10/11) and with Pd(II)-catalysts a 2,4-disubstituted furan (8/12) was formed. Only with perchloric acid the intermolecular addition of water to the allene, leading to 1,3-dicarbonyl compounds 7, was observed. While with the corresponding allenyl o-methoxybenzyl ketone 3b the Ag(I)- and Pd(II)-catalysts provided the expected products, the mercury-catalyst led to a new and interesting side-product rac-17 which combined both the furan moiety and the spiro[4.5]decene moiety. Efforts to prepare allenyl hydroxybenzyl ketones failed, in one case a small amount of a 5H-benzo[b]oxepin-4-one 21 was isolated. It also was not possible to extend the spirocyclization to allenyl p-siloxyphenyl ketone 6a or allenyl 2-(p-siloxyphenyl)ethyl ketone 6c.