Cyclopentannulations leading to the synthesis of bicyclic conjugated enediones.
摘要:
Base-induced reactions of 1-(phenylsulfonyl)-2-methylene-3-bromopropane (4) with 2-(phenylsulfonyl)-2-cycloalkenones 8a-d were investigated with the ultimate purpose to develop a route leading to bicyclic conjugated enediones. Low-temperature, fast-quenched reactions led generally to open-chain adducts, while increase of temperature and addition of HMPA resulted in subsequent ring closure by a tandem Michael-S(N)2 process. The stereochemical features of the bicyclo[3.3.0]octanes 11 and 12, bicyclo[4.3.0]nonanes 18 and 19, bicyclo[5.3.0]decanes 22 and 23, and bicyclo[6.3.0]-undecanes 26-28 thus obtained have been determined. Ozonolysis and silica-induced elimination of the tertiary phenylsulfonyl group converted stereoselectively the above products into the desired enediones: pentalenedione 29, indenedione 30, azulenedione 32 and cyclopentacyclooctenedione 33, respectively.
An Efficient Synthesis of <i>p</i><i>eri</i>-Hydroxy Aromatic Compounds via a Strong-Base-Induced [4+2] Cycloaddition of Homophthalic Anhydrides with Enolizable Enones
作者:Kiyosei Iio、Namakkal G. Ramesh、Akiko Okajima、Kazuhiro Higuchi、Hiromichi Fujioka、Shuji Akai、Yasuyuki Kita
DOI:10.1021/jo990649q
日期:2000.1.1
An efficient synthesis of peri-hydroxy aromatic compounds has been accomplished via a strong-base-induced [4+2] cycloaddition of homophthalic anhydrides with alpha-sulfinyl-substituted derivatives of enolizable enones. The unsubstituted enones did not undergo an efficient [4+2] cycloaddition reaction with homophthalic anhydrides, presumably due to their enolization under the basic reaction conditions
A strong-base induced [4+2] cycloaddition of homophthalic anhydrides with enolizable enones: a direct and efficient synthesis of peri-hydroxy aromatic compounds
作者:Namakkal G. Ramesh、Kiyosei Iio、Akiko Okajima、Shuji Akai、Yasuyuki Kita
DOI:10.1039/a807095d
日期:——
A direct and efficient synthesis of peri-hydroxy aromatic compounds via a strong-base induced [4+2] cycloaddition of homophthalic anhydrides with α-phenylsulfinyl enolizable enones has been accomplished.
The First Observation of γ-Sila-Pummerer Rearrangement
作者:Maciej Mikina
DOI:10.1080/10426507.2012.744310
日期:2013.4.1
2-Sulfinyl-3-trimethylsilylmethylcycloalkanones unexpectedly undergo -sila-Pummerer rearrangement. The first examples of this new type of rearrangement are presented.