The quest for planarizing distortions in hydrocarbons: two stereoisomeric [4.5.5.5]fenestranes
摘要:
According to semiempirical calculations the planarizing distortions in the central C(C)4 substructure of fenestranes, represented as 1, can be enhanced by a variety of structural modifications. Based on these results we selected the 7-hydroxy-c,c,c,c- and c,t,c,c[4.5.5.5]fenestranones 13 and 16 as precursors for the introduction of a bridgehead double bond. The efficient synthesis of these precursors and their chemical transformations are reported. Attempts to activate the hydroxyl group in 16 for introduction of a bridgehead double bond led to the rearrangement of the [4.5.5.5]fenestrane to a triquinacane skeleton. (C) 2011 Elsevier Ltd. All rights reserved.
The quest for planarizing distortions in hydrocarbons: two stereoisomeric [4.5.5.5]fenestranes
摘要:
According to semiempirical calculations the planarizing distortions in the central C(C)4 substructure of fenestranes, represented as 1, can be enhanced by a variety of structural modifications. Based on these results we selected the 7-hydroxy-c,c,c,c- and c,t,c,c[4.5.5.5]fenestranones 13 and 16 as precursors for the introduction of a bridgehead double bond. The efficient synthesis of these precursors and their chemical transformations are reported. Attempts to activate the hydroxyl group in 16 for introduction of a bridgehead double bond led to the rearrangement of the [4.5.5.5]fenestrane to a triquinacane skeleton. (C) 2011 Elsevier Ltd. All rights reserved.
β-enaminones is presented: in the presence of tetraethyl orthosilicate, a number of highly functional β-enamino esters were obtained; this method provided an alternative for the formation of β-amino-α,β-unsaturated carbonyl compounds with mild and functional group compatible reaction conditions.
Iodo cyclofunctionalization of 2,4-dialkenyl-1,3-dicarbonyl compounds: Synthesis of substituted 3-(2-furylidene)-2-furanones
作者:Claudete J. Valduga、Hélio A. Stefani、Nicola Petragnani
DOI:10.1002/jhet.5570390406
日期:2002.7
A facile method for the synthesis of substituted3-(2-furylidene)-2-furanones has been developed using cyclofunctionalization reactions of 2,4-dialkenyl-1,3-dicarbonylcompounds and iodine as electrophile in the presence of Na2CO3, in refluxing chloroform. Compounds 4 are obtained in modest to good yields and their structural identification was established by 1H NMR, 1H COSY, 13C NMR and 1H-13C COSY
在Na 2 CO 3存在下,利用2,4-二烯基-1,3-二羰基化合物和碘作为亲电子试剂的环官能化反应,已经开发了一种简便的合成取代的3-(2-呋喃基)-2-呋喃酮的方法。,在回流的氯仿中。以中等至良好的产率获得化合物4,并通过1 H NMR,1 H COSY,13 C NMR和1 H- 13 C COSY建立其结构鉴定。已经提出了一种使亚基呋喃酮的形成合理化的机制。
Seleno and Telluro Cyclofunctionalization of α,γ-Diallyl-β-ketoesters: Polysubstituted Furan Derivatives
作者:Hblio A. Stefani、Nicola Petragnani、Carlos A. Brandt、Daniela G. Rando、Claudtte J. Valduga
DOI:10.1080/00397919908085985
日期:1999.10
Abstract Seleno- and telurocyclofunctionalized furan derivatives were prepared by reaction of phenylselenenyl bromide and p-methoxyphenyl tellurium trichloride with α,γ-diallyl-β-ketoesters in good yield.
Constituents of Pyrethrum Flowers. XXIV. Synthetic dl-cis-Cinerolone and Other Cyclopentenolones<sup>1,2</sup>
作者:Milton S. Schechter、Nathan Green、F. B. LaForge
DOI:10.1021/ja01139a050
日期:1952.10
Iodine promoted cyclofunctionalization reaction of 2,4-dialkenyl-1,3-dicarbonyl compounds
作者:Hélio A. Stefani、Nicola Petragnani、Claudéte J. Valduga、Carlos A. Brandt
DOI:10.1016/s0040-4039(97)01079-4
日期:1997.7
The reactions of 2,4-dialkenyl-1,3-dicarbonyl compounds with I-2 lead to 5-iodoalkyl-4,5-dihydrofuran rings in good yield under mild conditions. (C) 1997 Elsevier Science Ltd.