Access to 6-Deoxy-heptose Constructs by One Carbon Homologation of Hexoses with Malononitrile: Divergent Synthesis of Campylobacter jejuni Strain 81-176 Capsular Trisaccharide Repeating Unit Derivatives

Abstract

An efficient approach to 6-deoxy-heptose constructs has been established by one-carbon homologation of the sugar chain of hexoses. The reaction features the formation of sugar-based α-substituted propanedinitriles and ensuing diverse oxidative transformations under mild reaction conditions that are compatible with a wide range of sugars bearing various functional/protecting groups. The applications of this method are demonstrated by a divergent assembly of Campylobacter jejuni strain 81-176 capsular trisaccharide repeating unit derivatives.

Modular Synthesis of Congested b2,2-Amino Acids via the Merger of Photocatalysis and Oxidative Functionalisations

“…To further highlight the adaptability and flexibility of our approach, we successfully showcased the capability to directly synthesize N-protected β-amino acids by adjusting the conditions during the second step of the process. Using H2O2 as a mild oxidant, [25] it is possible to access b 2,2 -amino acids bearing (hetero)cyclic cores (18-23). [26] Moreover, both acyclic ketones (24), as well as aldehydes (25)(26), can be used to access the corresponding b-amino acids.…”

“…Using H2O2 as a mild oxidant, [25] it is possible to access b 2,2 -amino acids bearing (hetero)cyclic cores (18-23). [26] Moreover, both acyclic ketones (24), as well as aldehydes (25)(26), can be used to access the corresponding b-amino acids. In addition, the modularity of our strategy was further highlighted by replacing Cbz-glycine by an unnatural amino acid bearing a piperazinone core in the first step, thus enabling the synthesis of highly polar b 2,2 -amino acid 27 in 38% yield.…”

Modular synthesis of congested β2,2-amino acids via the merger of photocatalysis and oxidative functionalisations

“…To expand the practicality of the method, N-protected bamino acids were prepared directly using H 2 O 2 as the oxidant (18)(19)(20)(21)(22)(23). 19,20 Both acyclic ketones (24), as well as aldehydes (25-26), can be used to access the corresponding b-amino acids.…”

“…To expand the practicality of the method, N-protected bamino acids were prepared directly using H 2 O 2 as the oxidant (18)(19)(20)(21)(22)(23). 19,20 Both acyclic ketones (24), as well as aldehydes (25-26), can be used to access the corresponding b-amino acids. In addition, the modularity of our strategy was further highlighted by replacing Cbz-glycine by an unnatural amino acid bearing a piperazinone core in the first step, thus enabling the synthesis of highly polar b 2 -amino acid 27 in 38% yield.…”