Abstract:Die orientalische Pflanze Yuzuriha (Daphniphyllum macropodum) bildet eine Gruppe faszinierender polycyclischer, vom Squalen abgeleiteter Alkaloide, an denen sich der Stand der organischen Synthesechemie messen laBt. Die bezaubernden Strukturen dieser Naturstoffe haben uns dazu angeregt, zwei ziemlich verschiedene Synthesen zu entwerfen und zu untersuchen. Dieser Ubersichtsartikel stellt beide Synthesewege vor und vergleicht sie miteinander. Dem ersten Ansatz lag eine Syntheseplanung auf der Basis von Coreys Ne… Show more
“…The term concession step is applied to these types of reactions since it is well accepted that they require extra effort but are often simply unavoidable. To substantiate the principle of “ideality” in synthesis, the trend-setting synthesis of daphniphyllum alkaloids by Heathcock et al is showcased in Scheme . The synthesis of dihydro-protodaphniphylline ( 9 ) starts with two C−C bond formations between the lithium enolate of tert -butyl acetate and 1 , followed by an alkylation of 3 with 4 , to give after acid hydrolysis compound 5 .…”
Section: Attempting To Quantify the Ideal Synthesismentioning
The field of total synthesis has a rich history and a vibrant future. Landmark advances and revolutionary strides in the logic of synthesis have put the practicing chemist in the enviable position of being able to create nearly any molecule with enough time and effort. The stage is now set for organic chemists to aim for "ideality" in the way molecules are synthesized. This perspective presents a simple and informative definition of "ideality" and demonstrates its use during the self-evaluation of several syntheses from our laboratory.
“…The term concession step is applied to these types of reactions since it is well accepted that they require extra effort but are often simply unavoidable. To substantiate the principle of “ideality” in synthesis, the trend-setting synthesis of daphniphyllum alkaloids by Heathcock et al is showcased in Scheme . The synthesis of dihydro-protodaphniphylline ( 9 ) starts with two C−C bond formations between the lithium enolate of tert -butyl acetate and 1 , followed by an alkylation of 3 with 4 , to give after acid hydrolysis compound 5 .…”
Section: Attempting To Quantify the Ideal Synthesismentioning
The field of total synthesis has a rich history and a vibrant future. Landmark advances and revolutionary strides in the logic of synthesis have put the practicing chemist in the enviable position of being able to create nearly any molecule with enough time and effort. The stage is now set for organic chemists to aim for "ideality" in the way molecules are synthesized. This perspective presents a simple and informative definition of "ideality" and demonstrates its use during the self-evaluation of several syntheses from our laboratory.
“…Daphniphyllum alkaloids such as daphniphylline and yuzurimine possess unique ring systems and have attracted great interest from a biogenetic point of view. , These stimulating polycyclic skeletons have prompted extensive synthetic work. Heathcock and co-workers demonstrated an extraordinary transformation into these alkaloids by using three elementary reagents, potassium hydroxide, ammonia, and acetic acid . These results indicate that a similar process might be an important step in the biosynthesis of the Daphniphyllum alkaloids.…”
Two novel alkaloids with a unique aza-adamantane core, daphnezomines A (1) and B (2), have
been isolated from the leaves of Daphniphyllum humile, and the structures including relative
stereochemistry were elucidated on the basis of spectroscopic data and chemical means. The absolute
configuration of 2 was established by X-ray crystallographic analysis.
“…Untersucht man früher postulierte Biogenesewege aus diesem neuen Blickwinkel, so lässt sich leicht ersehen, wo Aminozyme in die Biosynthese eingreifen könnten. Ein anschauliches Beispiel kann in Heathcocks Vorschlag für die Biosynthese der Daphniphyllum ‐Alkaloide gefunden werden 28. Hier könnte ein Aminozym an einer Enamin‐basierten asymmetrischen Michael‐Reaktion beteiligt sein, die über das Heathcock‐Intermediat II verläuft (Schema ).…”
Section: Ist Die Urtümliche Asymmetrische Organokatalyse Ein Erhaltenunclassified
Ein Weg mit drei Abzweigen: Die Hajos‐Wiechert‐Reaktion gab ein Rätsel auf, das über drei Jahrzehnte ungelöst blieb. Heute, wo wir diese Reaktion verstehen, kommt der Organokatalyse eine zentrale Rolle bei der Entwicklung von effizienten katalytischen asymmetrischen Methoden zu. Der Mechanismus der Organokatalyse gibt auch Aufschluss über die Ursprünge der Homochiralität und über bis dato unbekannte Biosynthesemechanismen, die in heutigen Organismen aktiv sein könnten.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.