65939-59-5Relevant articles and documents
Bicyclic nucleoside inhibitors of varicella-zoster virus (VZV): Effect of terminal unsaturation in the side-chain
Srinivasan,McGuigan,Andrei,Snoeck,De Clercq,Balzarini
, p. 763 - 766 (2001)
As part of an ongoing research program, we have prepared novel bicyclic nucleoside inhibitors bearing long alkyl side-chains for evaluation against VZV. In particular, we report the synthesis of analogues with terminal unsaturation in the side-chain. Terminal alkenyl derivatives were found to be potent antivirals whereas the terminal alkynyls displayed poor activity.
Syntheses of 2-silicon-substituted 1,3-dienes
Choudhury, Partha P.,Junker, Christopher S.,Pidaparthi, Ramakrishna R.,Welker, Mark E.
, p. 88 - 93 (2014/02/14)
A number of 2-silicon substituted 1,3-dienes have been prepared by one of three routes: 1) Reactions of 1,3-dienyl Grignard reagents with silyl electrophiles or silyl Grignard reagents with 1,3-dienyl electrophiles; 2) Hydrosilylation of enynes; 3) Enyne cross metathesis. The strengths and limitations of each preparative method are discussed.
The consecutive cyclization-elimination reaction of a radical generated from an epoxide: stereospecific formation of an exocyclic alkene
Lowinger, Timothy B.,Weiler, Larry
, p. 1636 - 1637 (2007/10/02)
A titanium(III) mediated radical cyclization-elimination reaction is reported, which allows for the efficient generation of functionalized cyclopentane derivatives.The reaction is highly stereospecific, giving excellent control over the geometry of the resulting exocyclic alkene.In addition, functionality at both reacting termini is retained for subsequent transformations.
Chemistry of 1-Carbena-5-hexyne and Related Intermediates
Freeman, Peter K.,Danino Jose C.,Stevenson, Brian K.,Clapp, Gary E.
, p. 3867 - 3875 (2007/10/02)
Pyrolysis of the lithium salt of the tosylhydrazone of 4,4-dimethyl-6-heptyn-2-one (6b) as the dry salt over a temperature range of 150 to 200 deg C formed 4,4-dimethyl-1-hepten-6-yne (8), cis-4,4-dimethyl-5-hepten-1-yne (9), and trans-4,4-dimethyl-5-hepten-1-yne (10) with an average acyclic enyne composition of 11.1:4.9:84.0.The fourth product component, 1,5,5-trimethyl-1,3-cyclohexadiene (11a), was formed in 22-28percent relative to the acyclic enyne fraction.In order to test for a carbene to carbene equilibration, the lithium and sodium salts of 3,5,5-trimethyl-2-cyclohexenone tosylhydrazone were pyrolyzed.The lithium (sodium) salt formed 95.2percent (96.7percent) 11 and 4.8percent (3.3percent) 5,5-dimethyl-1-methylene-2-cyclohexene (19).Pyrolysis of the sodium salt of 4,4-dimethyl-6-heptyn-2-one (6c) generated an increased amount of cyclic product exhibiting a product composition of 72.0percent 11a, 8.7percent 8, 2.3percent 9, and 17.0percent 10, whereas the pyrolysis of 6c in the presence of 3.0 equiv of LiBr produced a product composition poorer in cyclic product (34.6percent 11a, 13.2percent 8, 5.2percent 9, and 47.2percent 10).Thermolysis of the lithium (sodium) salt of the tosylhydrazone of 2-heptanon-6-yne generates products with a reaction composition of 4.8percent (47.8percent) 1-methyl-1,3-cyclohexadiene (11b), 8.1percent (5.9percent) 1-hepten-6-yne (21), 29.9percent (11.4percent) cis-5-hepten-1-yne (22), and 57.3percent (35.1percent) trans-5-hepten-1-yne (23).In order to characterize the alkynylcarbenes formed in these decompositions, the related saturated systems were investigated by pyrolysis of the lithium and sodium salts of the tosylhydrazones of 2-heptanone and 4,4-dimethyl-2-heptanone.The mechanistic pathways for the decomposition of 2-diazo-4,4-dimethyl-1-heptyne are described in terms of (a) a pyrazole route and (b) a carbene to carbene rearrangement.
Novel Bicyclization of Enynes and Diynes Promoted by Zirconocene Derivatives and Conversion of Zirconabicycles into Bicyclic Enones via Carbonylation
Negishi, Ei-ichi,Holmes, Steven J.,Tour, James M.,Miller, Joseph A.,Cederbaum, Fredrik E.,et al.
, p. 3336 - 3346 (2007/10/02)
Enynes and diynes react with "ZrCp2" (where Cp = η5-C5H5) generated by treating Cl2ZrCp2 with Mg and HgCl2 or 2 equiv of an alkyllithium, such as n-BuLi, or a Grignard reagent, such as EtMgBr, and can produce in excellent yields zirconabicycles represented by 2 (M = Zr) and 8, respectively.Their protonolysis can provide the corresponding exocyclic alkenes and conjugated dienes 9, respectively.Iodinolysis of 2 (M = Zr) can give the corresponding diiodides in high yields, while carbonylation of 2 (M = Zr) can produce bicyclic enones 3 (Y = O) in moderate to goodyields.Although the bicyclization reaction fails with terminal alkyne containing substrates, various types of substituents on the alkyne moiety, such as alkyl, alkenyl, aryl, trialkylsilyl, and trialkylstannyl groups, can be accommodated.Investigation of the n-BuLi-Cl2ZrCp2 reaction has revealed that is gives first (n-Bu)2ZrCp2 at -78 deg C, which then decomposes to give Cp2Zr(CH2=CHEt), identified as its PMe3 complex 11.The PMe3-stabilized complex reacts with diphenylacetylene to produce a crystalline compound which has been identified as a zirconacyclopropene, 36a.This demonstrated, for the first time, the feasibility of converting alkynes into zirconacyclopropenes.The reaction of preformed, three-membered zirconacycles with alkynes gives five-membered zirconacycles.The reaction of diphenylacetylene is ca. 150 times as fast as that of (E)-stilbene.These results support a mechanism involving formation of a zirconacyclopropene intermediate followed by its intramolecular carbometalation with the alkene moiety of enynes for the Zr-promoted bicyclization of enynes.
Stereochemistry of Intramolecular Cyclopropanation of an Organoiron Reagent
Iyer, Ramnath S.,Kuo, Gee-Hong,Helquist, Paul
, p. 5898 - 5900 (2007/10/02)
Intramolecular cyclopropanation using an iron carbene precursor resultsin formation of a trans-fused methanodecal in system.
