An economical process for producing (2- and/or 1-)cyclohexenyl methyl ketones which are intermediates for the synthesis of &agr;- or &bgr;-damascone. In the presence of a catalyst, a 3-cyclohexenyl methyl ketone represented by the following formula (1a):
1
wherein, R
1
, R
2
and R
3
each independently represents a hydrogen atom or a methyl group and at least two of R
1
, R
2
and R
3
are methyl groups, is isomerized.
Studies of Diastereoselectivity in Diels−Alder Reactions of Enantiopure (S<i>S</i>)-2-(<i>p</i>-Tolylsulfinyl)-1,4-naphthoquinone and Chiral Racemic Acyclic Dienes
作者:M. Carmen Carreño、Susana García-Cerrada、Antonio Urbano、Claudio Di Vitta
DOI:10.1021/jo000210u
日期:2000.7.1
Enantiopure sulfinylnaphthoquinone (+)-5 reacted with racemic acyclic dienes 1a-f bearing a stereogenic allylic center, through a tandem cycloaddition/pyrolytic sulfoxide elimination, to afford optically enriched compounds 8a-f and 9a-f with good like/unlike selectivities (ca. 75:25) and good enantiomeric excesses (68-82%), arising from the partial kinetic resolution of the racemic dienes. The opposite
Condensation of Conjugated Enones With Diethyl Aminomalonate: A New and Convenient Access to 2,2-Bis(ethoxycarbonyl)-3,4-dihydro-2<i>H</i>-pyrroles
作者:Gaston Bedel Itoua、Jean-Yves Laronze
DOI:10.1055/s-1987-27941
日期:——
2,2-Bis-(ethoxycarbonyl)-3,4-dihydro-2H-pyrroles are prepared from conjugated enones and diethyl aminomalonate by a one-step cyclocondensation reaction. Reduction of the products with sodium cyanoborohydride affords the corresponding pyrrolidines.
An economical process for producing (2- and/or 1-)cyclohexenyl methyl ketones which are intermediates for the synthesis of α- or β-damascone. In the presence of a catalyst, a 3-cyclohexenyl methyl ketone represented by the following formula (1a):
wherein, R1, R2 and R3 each independently represents a hydrogen atom or a methyl group and at least two of R1, R2 and R3 are methyl groups, is isomerized.