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Bimolecular nature of boron trifluoride catalyzed glycosylation of a galactosyl donor: The role of the acceptor
Author(s) -
Li Haichen,
Qiao Yuanyuan
Publication year - 2013
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.24422
Subject(s) - chemistry , acceptor , glycosyl donor , boron trifluoride , catalysis , glycosylation , ring (chemistry) , density functional theory , hydrogen bond , stereochemistry , computational chemistry , photochemistry , glycosyl , organic chemistry , molecule , biochemistry , physics , condensed matter physics
Density functional theory (DFT) computations disclose the mechanism of a crucial neighboring participation step in BF 3 catalyzed stereoselective glycosylation of 1,2‐cyclopropaneacetylated galactosyl donor. Two tandem S N 2 displacements comprise this step: first, the glycosyl acceptor attacks the BF 3 ‐activated donor to break the donor's 1,2‐cyclopropane ring; then, the donor's 2‐acetyl oxygen substitutes the acceptor to accomplish the neighboring participation. A donor–acceptor hydrogen bond has been found to lower the overall activation free energy. This mechanism is preferred over a 2‐acetyl oxygen coface S N 2 displacement mechanism, in which no glycosyl acceptor is involved. © 2013 Wiley Periodicals, Inc.