Open AccessAlkynylation of Pentose Derivatives with Stereochemical Fidelity: Implications for the Regioselectivity of Alkynyl Diol Cycloisomerizations to Cyclic Enol Ethers
Author(s) -
Frank E. McDonald,
Dian Ding,
Andrew J. Ephron,
John Bacsa
Publication year - 2019
Publication title -
organic letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.94
H-Index - 239
eISSN - 1523-7060
pISSN - 1523-7052
DOI - 10.1021/acs.orglett.9b01024
Subject(s) - chemistry , regioselectivity , epimer , reagent , diol , enol , lithium (medication) , alkyne , yield (engineering) , stereochemistry , organic chemistry , combinatorial chemistry , catalysis , medicine , materials science , metallurgy , endocrinology
This work characterizes a previously undetected epimerization in the preparation of alkynyl diols from pentose precursors utilizing the Ohira-Bestmann reagent. Lithium trimethylsilyldiazomethane (Colvin reagent) additions to the d-ribose and d-lyxose-derived benzylidene acetals provide the respective alkynyl diol stereoisomers, without epimerization. Regioselective tungsten-catalyzed cycloisomerizations of the d-ribose- and d-lyxose-derived alkynyl diols yield rigid bicyclic pyranose glycals, confirming the stereochemical fidelity of the Colvin alkynylation process.