25435-63-6Relevant academic research and scientific papers
Regioselectivity of the Singlet Oxygen Ene Reaction (Schenck Reaction) with Vinylsilanes
Adam, Waldemar,Richter, Markus J.
, p. 3335 - 3340 (2007/10/02)
The ene reaction of singlet oxygen and vinylsilanes 1 with various substitution patterns and double-bond geometry has been studied. β-Silyl allylic hydroperoxides 2 were the major products of the photooxygenation, accompanied by smaller amounts of α,β-unsaturated ketones 3.The latter derive from decomposition of the regioisomeric α-hydroperoxy silanes 4 by elimination of silanol.Regioselectivities up to 97:3 were observed for vinylsilanes with a methyl group geminal to the silyl group and with cyclic derivatives.Z-Configurated substrates showed lower regioselectivity and reactivity.Elongation of the carbon chain at the geminal position also increased the amount enone formed.These results are rationalized in terms of stereoelectronic effects imposed by the silyl group on the ring-opening of the perepoxide intermediate.
Carbocyclic ring expansion reactions via free radical pathways - Part III
Baldwin, Jack E.,Adlington, Robert M.,Singh, Rajinder
, p. 3385 - 3412 (2007/10/02)
The free radical ring expansion methodology recently described1, leading to the formation of medium sized ring ketones from cyclohexanone precursors has been applied to different side chains and ring sizes. In addition precursors based on lactone rings have been prepared and subjected to radical forming reaction conditions.
Cross-Condensation Reactions of Cycloalkanones with Aldehydes and Primary Alcohols under the Influence of Zirconocene Complexes.
Nakano Tatsuya,Irifune Shinji,Umano Shigetoshi,Inada Akihiro,Ishii Yasutaka,Ogawa Masaya
, p. 2239 - 2244 (2007/10/02)
Under the influence of zirconocene complex,Cp2ZrH2 (1) or Cp2Zr(O-i-Pr)2 (9),cycloalkanones 2 condensed directly with aliphatic aldehydes 3 or primary alcohols 7 to form 2-alkylidenecycloalkanones 4 or 2-alkyl-2-cycloalken-1-ones 8,respectively,in fair to substantial yields.The selectivity of the cross-condensations was slighty improved by using 1 in combination with a metal salt such as NiCl2.Dihydrojasmone (13) was synthesized in 35percent yield by one-step reaction from the commercially available 3-methylpentanone (2e) with pentanol (7b) in the presence of 1 and NiCl2.
Strategic Synthesis based on Cyclohexadienes: Preparation of 2-, 2,3- and 2,4-Substituted Cyclohexenones; Synthesis of (Z)-Heneicosa-6-en-11-one
Pramod, Kakumanu,Ramanathan, Halasya,Rao, G. S. R. Subba
, p. 7 - 10 (2007/10/02)
The mesomeric anions, generated from 1-methoxycyclohexa-1,4-diene, 1-methoxy-5-methylcyclohexa-1,4-diene, and 1-methoxy-4-methylcyclohexa-1,4-diene with potassium amide in liquid ammonia, have been readily alkylated and the resulting dienes were hydrolysed to yield 2-alkyl-, 2,3-dialkyl- and 2,4-dialkyl-cyclohex-2-enones in good yield.Arylation of the above mesomeric anions followed by hydrolysis afforded 2-arylcyclohex-2-enones in addition to substituted biphenyls.A new and efficient synthesis of the male sex attractant of the Douglas Fir Tussock Moth, (Z)-heneicosa-6-en-11-one is described using the above methodology.
REGIOSPECIFIC CARBON-CARBON BOND FORMATION AT α AND β POSITIONS IN CYCLIC KETONES VIA DOUBLE MICHAEL ADDITION TO α-METHYLENE-β-ALKOXY CYCLIC KETONE
Takahashi, Takashi,Hori, Kimihiko,Tsuji, Jiro
, p. 119 - 122 (2007/10/02)
Very reactive 2-methylene-3-alkoxycyclohexanone was synthesized.The 1,4-conjugate addition of various nucleophiles to this enone gave only β'-alkylated 2-cyclohexenone with simultaneous elimination of the β-alkoxy group.The second 1,4-conjugate addition of other nucleophile to the resulting cyclohexenone leads to the α and β disubstituted ketones.
