5 research outputs found
Unexpected 5,6,7,8,9,10-Hexahydro-6,6-pentamethylenephenanthridines and 2,3,4,5-Tetrahydro-4,4-tetramethylene-1<i>H</i>-cyclopenta[<i>c</i>]quinolines from Skraup–Doebner–Von Miller Quinoline Synthesis and Their Implications for the Mechanism of That Reaction
The real mechanism of the Skraup–Doebner–Von
Miller
quinoline synthesis remains controversial and not well understood
despite several mechanistic studies reported on the matter. A series
of unexpected and unusual 5,6,7,8,9,10-hexahydro-6,6-pentamethylenephenanthridines
and 2,3,4,5-tetrahydro-4,4-tetramethylene-1<i>H</i>-cyclopentaÂ[<i>c</i>]Âquinolines have been obtained through the Skraup–Doebner–Von
Miller quinoline synthesis. On the basis of these unexpected results
and in agreement with some of the previously reported quinoline syntheses,
an alternative mechanistic pathway is proposed for this variant of
the reaction. It involves the formation of a Schiff base through a
reaction between the ketone and the aniline derivative in the first
step, followed by a cycloalkenylation at the <i>ortho</i>-position to the amine functional group of the aniline derivative,
and an annulation in the final step to close the quinoline ring, leading
to a dihydroquinoline derivative. To the best of our knowledge, this
is the first report of such a mechanistic pathway being proposed for
any variant of the Skraup–Doebner–Von Miller quinoline
synthesis
Unexpected 5,6,7,8,9,10-Hexahydro-6,6-pentamethylenephenanthridines and 2,3,4,5-Tetrahydro-4,4-tetramethylene-1<i>H</i>-cyclopenta[<i>c</i>]quinolines from Skraup–Doebner–Von Miller Quinoline Synthesis and Their Implications for the Mechanism of That Reaction
The real mechanism of the Skraup–Doebner–Von
Miller
quinoline synthesis remains controversial and not well understood
despite several mechanistic studies reported on the matter. A series
of unexpected and unusual 5,6,7,8,9,10-hexahydro-6,6-pentamethylenephenanthridines
and 2,3,4,5-tetrahydro-4,4-tetramethylene-1<i>H</i>-cyclopentaÂ[<i>c</i>]Âquinolines have been obtained through the Skraup–Doebner–Von
Miller quinoline synthesis. On the basis of these unexpected results
and in agreement with some of the previously reported quinoline syntheses,
an alternative mechanistic pathway is proposed for this variant of
the reaction. It involves the formation of a Schiff base through a
reaction between the ketone and the aniline derivative in the first
step, followed by a cycloalkenylation at the <i>ortho</i>-position to the amine functional group of the aniline derivative,
and an annulation in the final step to close the quinoline ring, leading
to a dihydroquinoline derivative. To the best of our knowledge, this
is the first report of such a mechanistic pathway being proposed for
any variant of the Skraup–Doebner–Von Miller quinoline
synthesis
Unexpected 5,6,7,8,9,10-Hexahydro-6,6-pentamethylenephenanthridines and 2,3,4,5-Tetrahydro-4,4-tetramethylene-1<i>H</i>-cyclopenta[<i>c</i>]quinolines from Skraup–Doebner–Von Miller Quinoline Synthesis and Their Implications for the Mechanism of That Reaction
The real mechanism of the Skraup–Doebner–Von
Miller
quinoline synthesis remains controversial and not well understood
despite several mechanistic studies reported on the matter. A series
of unexpected and unusual 5,6,7,8,9,10-hexahydro-6,6-pentamethylenephenanthridines
and 2,3,4,5-tetrahydro-4,4-tetramethylene-1<i>H</i>-cyclopentaÂ[<i>c</i>]Âquinolines have been obtained through the Skraup–Doebner–Von
Miller quinoline synthesis. On the basis of these unexpected results
and in agreement with some of the previously reported quinoline syntheses,
an alternative mechanistic pathway is proposed for this variant of
the reaction. It involves the formation of a Schiff base through a
reaction between the ketone and the aniline derivative in the first
step, followed by a cycloalkenylation at the <i>ortho</i>-position to the amine functional group of the aniline derivative,
and an annulation in the final step to close the quinoline ring, leading
to a dihydroquinoline derivative. To the best of our knowledge, this
is the first report of such a mechanistic pathway being proposed for
any variant of the Skraup–Doebner–Von Miller quinoline
synthesis
Stereospecific Suzuki, Sonogashira, and Negishi Coupling Reactions of <i>N</i>‑Alkoxyimidoyl Iodides and Bromides
A high-yielding
stereospecific route to the synthesis of single
geometric isomers of diaryl oxime ethers through Suzuki coupling of <i>N</i>-alkoxyimidoyl iodides is described. This reaction occurs
with complete retention of the imidoyl halide geometry to give single <i>E</i>- or <i>Z</i>-isomers of diaryl oxime ethers.
The Sonogashira coupling of <i>N</i>-alkoxyimidoyl iodides
and bromides with a wide variety of terminal alkynes to afford single
geometric isomers of aryl alkynyl oxime ethers has also been developed.
Several of these reactions proceed through copper-free conditions.
The Negishi coupling of <i>N</i>-alkoxyimidoyl halides is
introduced. The <i>E</i> and <i>Z</i> configurations
of nine Suzuki-coupling products and two Sonogashira-coupling products
were confirmed by X-ray crystallography
Stereospecific Suzuki, Sonogashira, and Negishi Coupling Reactions of <i>N</i>‑Alkoxyimidoyl Iodides and Bromides
A high-yielding
stereospecific route to the synthesis of single
geometric isomers of diaryl oxime ethers through Suzuki coupling of <i>N</i>-alkoxyimidoyl iodides is described. This reaction occurs
with complete retention of the imidoyl halide geometry to give single <i>E</i>- or <i>Z</i>-isomers of diaryl oxime ethers.
The Sonogashira coupling of <i>N</i>-alkoxyimidoyl iodides
and bromides with a wide variety of terminal alkynes to afford single
geometric isomers of aryl alkynyl oxime ethers has also been developed.
Several of these reactions proceed through copper-free conditions.
The Negishi coupling of <i>N</i>-alkoxyimidoyl halides is
introduced. The <i>E</i> and <i>Z</i> configurations
of nine Suzuki-coupling products and two Sonogashira-coupling products
were confirmed by X-ray crystallography