Versatile Synthesis and Mechanism of Activation of <i>S</i>-Benzoxazolyl Glycosides
作者:Medha N. Kamat、Nigam P. Rath、Alexei V. Demchenko
DOI:10.1021/jo0711844
日期:2007.8.31
As a part of a program for developing new efficient procedures for stereoselectiveglycosylation, a range of S-benzoxazolyl (SBox) glycosides have been synthesized. The mechanistic aspects of the SBox moiety activation for glycosylationvia a variety of conceptually different pathways in the presence of thiophilic, electrophilic, or metal-based promoters have been investigated.
Superarming the <i>S</i>-Benzoxazolyl Glycosyl Donors by Simple 2-<i>O</i>-Benzoyl-3,4,6-tri-<i>O</i>-benzyl Protection
作者:Laurel K. Mydock、Alexei V. Demchenko
DOI:10.1021/ol800345j
日期:2008.6.5
The strategic placement of common protecting groups led to the discovery of a new method for "superarming" glycosyl donors. Conceptualized from our previous studies on the O-2/O-5 Cooperative Effect, it was determined that S benzoxazolyl glycosyl donors possessing both a participating moiety at C-2 and an electronically armed lone pair at O-5, such as the superarmed glycosyl donor shown above, were exceptionally reactive.