94223-41-3Relevant academic research and scientific papers
Metal-catalyzed chemoselective cycloisomerization of cis-2,4-dien-1-als to 3-cyclopentenones and 4-alkylidene-3,4-dihydro-2H-pyrans
Lo, Ching-Yu,Lin, Chung-Chang,Cheng, Hsin-Mei,Liu, Rai-Shung
, p. 3153 - 3156 (2006)
PtCl2 (5 mol %) catalyst effected cycloisomerization of cis-2,4-dien-1-al (1) to 3-cyclopentenone (3) efficiently in hot toluene. In the presence of p-TSA, this PtCl2 catalysis gave 2-cyclopentenone (5) exclusively because of the secondary isomerization reaction. Although the 1-2 equilibrium state greatly favors aldehyde (1), PdCl2(PhCN) 2 (5 mol %) catalyzed cycloisomerization of aldehyde (1) to 4,6,7,8-tetrahydro-3H-isochromene (4) smoothly in hot toluene. A plausible mechanism is proposed on the basis of reaction observation and isotope-labeled experiment.
Metal-catalyzed cycloisomerization of enyne functionalities via a 1,3-alkylidene migration
Lin, Ming-Yuan,Das, Arindam,Liu, Rai-Shung
, p. 9340 - 9341 (2007/10/03)
We report a new metal-catalyzed 6-endo-dig cyclization of cis-4,6-dien-1-yn-3-ols, which produces substituted benzene and naphthalene derivatives with structural reorganization. In this process, we observe a 1,3-alkylidene migration via cleavage of the olefin double bond of the starting substrates. The ease and reliability of this cyclization are manifested by its compatibility with a wide array of diverse substrates and several π-alkyne activators, including PtCl2, Zn(OTf)2, AuCl, and AuCl3. Copyright
Ruthenium-catalyzed cycloisomerizations of diynols
Trost, Barry M.,Rudd, Michael T.
, p. 4763 - 4776 (2007/10/03)
A wide variety of diynols containing tertiary, secondary, and primary propargylic alcohols undergo a cycloisomerization reaction to form dienones and dienals in the presence of a catalytic amount of [CpRu(CH3CN) 3]PF6. The
An unusual ruthenium-catalyzed cycloisomerization of alkynes and propargyl alcohols
Trost, Barry M.,Rudd, Michael T.
, p. 4178 - 4179 (2007/10/03)
CpRu(NCCH3)3+PF6- catalyzes the cycloisomerization of diyne-ols to α,β,γ,δ-unsaturated aldehydes and ketones in good-to-excellent yields. 1-Hydroxy-2,7-diynes and 1-hydroxy-2,8-diynes can be utilized to form hig
A STUDY OF PERISELECTIVITY IN THE THERMAL CYCLISATION REACTIONS OF DIENE-CONJUGATED DIAZO COMPOUNDS: 1,7-CYCLISATION AS A ROUTE TO 3H-1,2-DIAZEPINES AND 1,5-CYCLISATION LEADING TO NEW REARRANGEMENT REACTIONS OF 3H-PYRAZOLES
Robertson, Ian R.,Sharp, John T.
, p. 3095 - 3112 (2007/10/02)
A range of diene-conjugated diazo compounds has been generated by the thermal decomposition of the sodium salts of the tosylhydrazones of 1-acyl-1,3-dienes. Those of type (21) with a cis relationship of the diazo group and the γ,δ-double bond and having a cis hydrogen atom at the dien terminus cyclised only by 1,7 ring closure to give 3H-1,2-diazepines (23).This mode of cyclisation was inhibited by the presence of cis methyl or phenyl groups at the diene terminus eg in (45). Compounds of this type cyclised by the alternative 1,5- ring closure to give 3-alkenyl-3H-pyrazoles eg (46) as primary products. These observations are explained on the basis of a helical transition state (54) for the 8? electron 1,7-electrocyclisation reaction. Diene-conjugated diazo compounds with a trans γ,δ double bond eg (32) also cyclised predominantly by 1,5-electrocyclisation to give 3-alkenyl-3H-pyrazoles eg (33). In most cases the 3H-pyrazoles rearranged under the reaction conditions via alkenyl group and hydrogen migrations to give 1H-pyrazoles eg (34) and (37).
