C-Glycosylidene derivatives (exo-glycals): Their synthesis by reaction of protected sugar lactones with tributylphosphonium ylids, conformational analysis and stereoselective reduction
For recent reviews on glycoamino acids see: e.g. (a) Schweizer F. Angew Chem. Int. Ed. 41:2002;230-253 (b) Gruner S.A.W., Locardi E., Lohof E., Kessler H. Chem. Rev. 102:2002;491-514.
For recent reviews on glycoamino acids see: e.g. (a)
For recent reviews on glycoamino acids see: e.g. (a) Schweizer F. Angew Chem. Int. Ed. 41:2002;230-253 (b) Gruner S.A.W., Locardi E., Lohof E., Kessler H. Chem. Rev. 102:2002;491-514.
(a) Bérces A., Whitfield D.M., Nukada T. Tetrahedron. 57:2001;477-491 (b) http://www.nrc.ca/ibs/6ring.html . The conformation of a six-membered ring can be expressed in spherical polar co-ordinates such that d indicates the amount of puckering; θ=0 or 180° corresponds to a chair; θ=90°, φ=60n (where n=0, 1, 2...) corresponds to a boat and θ=90°, φ=60(n+0.5) corresponds to a twist-boat. (Z)-4c gives d=0.92; φ=76° θ=88°.
The conformation of a six-membered ring can be expressed in spherical polar co-ordinates such that d indicates the amount of puckering; θ=0 or 180° corresponds to a chair; θ=90°, φ=60n (where n=0, 1, 2...) corresponds to a boat and θ=90°, φ=60(n+0.5) corresponds to a twist-boat. (Z)-4c gives d=0.92; φ=76° θ=88°.
(a) Bérces A., Whitfield D.M., Nukada T. Tetrahedron. 57:2001;477-491 (b) http://www.nrc.ca/ibs/6ring.html . The conformation of a six-membered ring can be expressed in spherical polar co-ordinates such that d indicates the amount of puckering; θ=0 or 180° corresponds to a chair; θ=90°, φ=60n (where n=0, 1, 2...) corresponds to a boat and θ=90°, φ=60(n+0.5) corresponds to a twist-boat. (Z)-4c gives d=0.92; φ=76° θ=88°.