Influence of the Hydrogen Bond on the Regioselectivity of Glycosylation

<none>

Programme Social programme Plenary speakers Keynote speakers 1st EuroCarb Young Researcher (ECYR) Workshop CarboMet Workshop Mini symposium: Glycobiology at the LUMC and beyond Favourites/Agenda

Social programme

Plenary speakers

Keynote speakers

1st EuroCarb Young Researcher (ECYR) Workshop

CarboMet Workshop

Mini symposium: Glycobiology at the LUMC and beyond

Favourites/Agenda

Photos

Venue & Travel Venue Accommodation City of Leiden Travel directions

Venue

Accommodation

City of Leiden

Travel directions

Committees

Home

Influence of the Hydrogen Bond on the Regioselectivity of Glycosylation

Kinga Kuczynska 1 , Zbigniew Pakulski 1

1 Institute of Organic Chemistry, Polish Academy of Sciences, Warszawa, Poland

It is known that hydroxyl groups in equatorial positions are more reactive than axially oriented ones. In our synthesis of lupane-type saponins bearing OSW-1 disaccharide unit we observed that glycosylation had preferentially taken place at 4-OH group of arabinopyranoside ring. Such reversed reactivity of some L-arabinopyranoside derivatives was reported and explained by an influence of bulky substituent at the O-2 position and/or inversion of the pyranoside ring which adopts unusual 1C4 conformation [1].

Here we propose that the formation of the hydrogen bond between anomeric oxygen atom and the 3-OH group is responsible for observed ring inversion. The presence of hydrogen bond was confirmed by the NMR studies. In this communication we will present the influence of hydrogen bond on the regioselectivity of glycosylation reaction. Plausible mechanism explaining such unusual regioselectivity will also be presented [2].

Scheme 1

The support from the National Science Centre (NCN), Poland (grant No: 2016/21/B/ST5/02141) is acknowledged.

(a) Wang, P.; Li, C.; Zang, J.; Song, N.; Zhang, X.; Li, Y. Carbohydr. Res. 2005, 340, 2086-2096. (b) Gauthier, C.; Legault, J.; Lavoie, S.; Rondeau, S.; Tremblay, S.; Pichette, A. Tetrahedron 2008, 64, 7386-7399. (c) Yan, M.-C.; Liu, Y.; Lu, W.-X; Wang, H.; Sha, Y.; Cheng, M.-S. Carbohydr. Res. 2008, 343, 780-784. (d) Liu, Q.; Wang, P.; Zhang, L.; Guo, T.; Lv, G.; Li, Y. Carbohydr. Res. 2009, 344, 1276-1281. (e) Wang, B.; Chun, J.; Liu, Y.; Han, L.; Wang, Y.; Joo, E.-J.; Kim, Y.-S.; Cheng, M. Org. Biomol. Chem. 2012, 10, 8822-8834. (f) Kim, M.; Lim, E.; Jung, M. Tetrahedron 2013, 69, 5481-5486.

(a) Pakulski, Z.; Cmoch, P. Tetrahedron 2015, 71, 4757-4769. (b) Kuczynska, K.; Rárová, L.; Oklešťková, J.; Cmoch, P.; Korda, A.; Pakulski, Z.; Strnad, M. Carbohydr. Res. 2016, 423, 49-69.

Contact eurocarb@eurocarb2019.com for general questions about EUROCARB2019, or codee@eurocarb2019.com for scientific questions.

Leiden University / Leiden Institute of Chemistry lic.leidenuniv.nl

European Carbohydrate Organisation

Congress by Design www.congressbydesign.com