Hans-Josef Altenbach

Phosphor- und schwefelsubstituierte allene in der synthese I: einfache synthese von β-ketophosphonaten aus 1-alkin-3-olen

Abstract Allenic phosphonates, readily accessible from 1-alkin-3-ols, the addition products of 1-alkines to aldehydes or ketones, can be transformed to β-ketophosphonates by nucleophilic addition of diethylamine and subsequent hydrolysis of the formed enamines.

Synthesis of a 2-hydroxymethyl-dihydropyridone-system as a flexible building block for the preparation of azasugars

Abstract m CPBA induced oxidative cyclization of the aminoalcohol 1a under complete stereocontrol, generating after acetal formation a new diastereomerically pure key intermediate 2b for the flexible synthesis of azasugars. 2b could be converted to protected rac -mannonojirimycin, 3 in only three steps.

Einfache, Regiospezifische synthese von cycloalkenonen aus lactonen

Abstract The reaction of lithiumalkylphosphonates with γ or δ-lactones followed by oxidation leads to 2,5- or 2,6-dioxophosphonates, which can be cyclized to cyclopentenones or cyclohexenones, respectively, constituting an easy, regiospecific route to cycloalkenones from lactones.

Phosphor- und schwefelsubstituierte allene. IV: Eine einfache Synthese von 2[5H]Furanonen und β-Methylen-γ-butyrolactonen durch Addition von Malonsäureester an Allensulfoxide

Zusammenfassung Sodium malonates add readily to allenic sulfoxides; the adducts - after being protonated or alkylated - can be induced to undergo an allylic rearrangement, which is followed by cyclization, to give unsaturated γ-butyrolactones.

Emanuel Vogel (1927–2011)

Emanuel Vogel,[1] Professor Emeritus of the University of Cologne, passed away on March 31, 2011 in Ettlingen near Karlsruhe after a long illness, but still unexpectedly. Tragically, he had just submitted his last publication, “From Small Carbocyclic Rings to Porphyrins—A Personal Account of 50 Years of Research”, which was dedicated to his adored mentor Rudolf Criegee and which can be viewed as his scientific legacy, to Angewandte Chemie.[2] This personal retrospective starts from Cope rearrangements and valence isomerism in small ring systems[3] and continues to the central topic of his research—aromaticity and the H ckel rule with 1,6-methano[10]annulene[4] as a prototype of bridged acenes[5] to porphycenes and other porphyrin derivatives.[6] In hindsight, the impressive development of his research seems guided by a logic and inevitability that is reserved for the bold and the lucky: from the norcaradiene–cycloheptatriene problem[7] to 1,6-methano[10]annulene and the bridged aromatic acenes with 14, 18, and 22 p electrons to pioneering work in the field of annulene chemistry; but also to oxepin–benzene oxide,[8] the arene oxides in general, and higher benzene oxides, from which the aromatic and olefinic eight-membered-ring heterocycles such as dioxocin and diazocins were accessible; from 1,6methnao[10]annulene to highly strained, unusual, and new ring systems such as benzocyclopropene and later a number of other long-sought p systems such as heptalenes and octalenes, and finally to porphyrin isomers. His research was sometimes systematic but often advanced erratically and by serendipity—a popular term he introduced into the chemical literature to describe unexpected reactions.[9] Vogel was drawn intuitively to interesting topics and had the talent to explore them systematically and to elucidate their place in the larger picture. His co-workers were amazed again and again by his instinct for interesting developments and the determined way in which he pursued new ideas and concepts with all his strength. As a purist, he was always interested in the core, the parent structure of a new system. He was especially excited when his basic research served as a starting point for the investigations of other scientists, whether in physical and theoretical chemistry (e.g. the investigation of the stereochemistry of the ring opening of cyclobutene derivatives and the valence isomerization as the experimental foundation for the Woodward–Hoffmann rules), in biochemistry and pharmacy (with arene oxides, which, after their successful synthesis, were determined to be central primary intermediates in the metabolism of aromatic compounds), or in medical applications (as with porphycenes as photosensitizers for photodynamic therapy). He was often ahead of his time; he thought in terms of mechanisms and was an early avid user of physical organic methods and new structure-elucidation techniques such as NMR spectroscopy and X-ray crystallography, and he was willing to work in an interdisciplinary atmosphere and cooperated with expert colleagues worldwide. In the expansion of annulene chemistry at the end of his career, with porphycene as an isomer of phorphyrin, he opened up a completely new area of chemistry, namely that of expanded, contracted, and isomeric phorphyrins.[6] This development, in which he was actively involved as a researcher even after reaching emeritus status, fascinated him because it formed a bridge to the “pigments of life”, as the porphyrins were once called by Alan R. Battersby. This research opened the door to a colorful cornucopia of related systems and their metal complexes all the way to new porphyrinoid macrocycles, and also created a path to practical applications. His life s work was dedicated to basic research, and so he was especially satisfied that one of his systems, a specific substituted porphycene, could be applied as a promising candidate in photodynamic therapy to treat tumors and dermatological disease; this application even made him cofounder of a company. When it came to light that he had, with his phorphycene, prepared an overlooked isomer that Linus C. Pauling had conceived of as early as 1944, as became clear in the recently edited notes of the two-time Nobel Laureate,[10] his excitement for his early discovery knew no bounds. Emanuel Vogel was born on December 2, 1927 in Ettlingen on the edge of the Black Forest, where he grew up and attended school. His interest in the natural sciences, especially chemistry, was apparent from an early age. After being drafted in the last years of World War II before the end of his schooling, he began to study chemistry in 1946 at the Technical University in Karlsruhe and completed his doctorate in 1952 under Rudolf Criegee. During graduate school he had spent time with Ralph A. Raphael as a visiting scholar at the University of Glasgow (Scotland). In 1955 he was a postdoctoral fellow with Arthur C. Cope at MIT in Cambridge, MA (USA). He returned to TU Karlsruhe, completed his Habilitation in 1957, and worked there as a lecturer until 1961. In that year, at the age of only 33, he was appointed to the coveted position of successor of the Nobel Laureate Kurt Adler as Chair of Organic Chemistry at the University of Cologne, where he was active in teaching and research until reaching emeritus status in 1993, after having declined in 1968—with a heavy heart, as he often related—a position as successor to his mentor Rudolf Criegee at TU Karlsruhe. He increased the worldwide visibility of the Chemical Institute in Cologne and brought prominent speakers to the city, mostly through the Emanuel Vogel Obituary