- Regioselective formation of optically active cycloheptatrienes by chiral tethered buechner reaction
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Optically active cycloheptatrienes were prepared by addition of the rhodium carbenoid to polysubstituted phenyl rings connected by a 2,4-pentanediol tether in sufficient regio- and stereoselectivity.
- Sugimura, Takashi,Ohuchi, Naoko,Kagawa, Masami,Hagiya, Kazutake,Okuyama, Tadashi
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p. 404 - 405
(2007/10/03)
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- THE FLOW THERMOLYSES OF 1-ISOBUTENYL ALKYNYL- AND 2-METHYLPHENYL ALKYNYL KETONES. SYNTHESIS OF METHYLENOMYCIN B
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The gas flow thermolyses of 1-isobutenyl alkynyl and 2-methylphenyl alkynyl ketones were found to lead to phenols and to cyclopentenones.The results are explained by a 5-ring carbene process (the known α-alkynone cyclization) and a 6-ring as well as a 5-ring addition process.The latter two (novel) processes are thought to be intramolecular "C-H to CC additions" in two directions.The 5-ring addition process was used in a short (but low yield) synthesis of methylenomycin B.
- Koller, Manuel,Karpf, Martin,Dreiding, Andre S.
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- The Gas-Flow Thermolysis of 1-Isobutenyl Alkynyl and 2-Methylphenyl Alkynyl Ketones. Synthesis of Methylenomycin B
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The gas-flow thermolysis of 1-isobutenyl alkynyl or 2-methyphenyl alkynyl ketones were found to lead to phenols and cyclopentenones or to naphthols and indanones, respectively.These conversions involve two cyclization processes so far unknown with α-alkynones; they are interpreted as intramolecular additions of an allylic or a benzylic C,H bond to a triple bond which may occur in two directions.In addition, the cyclopentenones formed by the α-alkynone cyclization, a known carbene process yielding 5-rings, were also found.The available evidence ruled out a carbene process yielding 6-rings.The addition process yielding 5-rings was applied to a short (but low yield) synthesis of methylenomycin B.
- Koller, Manuel,Karpf, Martin,Dreiding, Andre S.
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p. 560 - 579
(2007/10/02)
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