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NMR Spectroscopic Isotope Tracking Reveals Cascade Steps in Carbohydrate Conversion by Tin‐Beta
Author(s) -
Elliot Samuel G.,
Taarning Esben,
Madsen Robert,
Meier Sebastian
Publication year - 2018
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201701861
Subject(s) - chemistry , carbohydrate , kinetic isotope effect , isotopic labeling , aldol reaction , catalysis , hydride , tin , stereochemistry , combinatorial chemistry , organic chemistry , deuterium , metal , physics , quantum mechanics
Quantitative isotope tracking studies were used to investigate the reaction pathways that occur for Sn‐Beta‐catalyzed carbohydrate conversion to various α‐hydroxy esters. Experimental insight into the conversion of pentoses was sought (i) by identifying pathways based on isotope patterns in the reaction products and (ii) by probing asymmetric isotope incorporation into products. The results indicate that reaction intermediates remain coordinated to the active site throughout the reaction cascades, regardless of the reaction pathway. A predominant transformation of the C1 carbohydrate position to the C3 position of methyl lactate resembles enzymatic glycolysis. Likewise, the majority of retro‐aldol cleavage occurs from the carbohydrate in the ketose form, which again resembles biological glycolysis. In addition, various side‐activities are detected in Sn‐Beta‐catalyzed carbohydrate conversion, which include 5,1‐hydride and 1,2‐carbon shift of the carbohydrates.