Chirale Lactole, XII. Untersuchungen zur basenkatalysierten Glycolaldehydaldolisierung

Abstract

Chiral Lactols, XII. – Studies on the Aldolization of Glycolaldehyde Catalyzed by Bases Base‐catalyzed aldolization of the glycolaldehyde derivative 1 is studied under various reaction conditions. The resulting products, tetrose and hexose derivatives 2–11, are reduced to the corresponding sugar alcohols and analyzed by HPL chromatography. All experiments leading to a trimerization of 1 give threose 3 as major product among the tetroses and allose 4 among the hexoses. An exception is the reaction catalyzed by LiOH, in which trimerization of 1 to the corresponding hexose derivatives proceeds much slower and as products galactose 10 together with glucose 6 are favored above the other hexoses.

Etiology of Potentially Primordial Biomolecular Structures: From Vitamin B12to the Nucleic Acids and an Inquiry into the Chemistry of Life’s Origin: A Retrospective

“…above) 60. 70, 116 Oligonucleotide variants based on D ‐altrose and D ‐glucose were added to the project later (Figure 30), the former in response to observing that the configuration of a hydroxy group at position C‐2′ is critical to the pairing capability of such oligonucleotides, and the latter because glucose is supposedly the thermodynamically most stable among the aldohexoses.…”

Ätiologie potentiell primordialer Biomolekül‐Strukturen: Vom Vitamin B12zu den Nukleinsäuren und der Frage nach der Chemie der Entstehung des Lebens – ein Rückblick

“…Nur in diesen beiden Isomeren -bei obligat äquatorialer Lage der Nukleobase und der beiden Rückgratsubstituenten -nimmt die freie Hydroxygruppe in Stellung 3 die axiale Konformation ein, in welcher sie nicht zur Behinderung der Paarungskonformation Anlass geben kann, wie sie es in äquatorialer Lage tun würde. Die erste Wahl fiel auf d-Allose, denn sie steht konfigurativ (relativ und absolut) der d-Ribose am nächsten, was sich in der Tatsache reflektiert, dass das rac-Allosederivat in Aldolisierungsexperimenten mit Glycolaldehydphosphat das Hauptprodukt darstellt (Abbildungen 16-18), [60,70,116] ebenso Abbildung 29. Vergleich der thermodynamischen Daten der Duplexierung von Einzelsträngen gleicher Basensequenz in der homo-DNA und der DNA-Reihe: Die fast durchgehend negativeren DG-Werte in der homo-DNA-Reihe sind durch entsprechende Unterschiede in den DS-Werten bedingt.…”

Investigation of an Unexpected Addition Reaction That Occurs when 2,3:4,5-Di-O-isopropylidene-d-ribose Diethyl Dithioacetal Is Treated with Mercuric Oxide and Mercuric Chloride

“…Recent interest in the aldol reaction as an approach to the synthesis of complex carbohydrates has focused on aldolase-catalyzed reactions [14][15][16][17][18] as well as on basecatalyzed aldol reactions involving nonidentical reaction partners. [19][20][21][22][23][24][25] The latter approach has typically involved the addition of a ketone enolate to an aldehyde, 19,20,24,25 although enolates derived from aldehydes 21 and esters 22,23 have also been employed. Much less attention has been given to aldol reactions starting from identical carbohydrate derivatives.…”