2-Alkoxycarbonylallyltrimethylsilanes as new reagents of 2-alkoxycarbonylallylation of electrophiles

2-Alkoxycarbonylallylsilanes are useful for 2-alkoxycarbonylallylation of acetals and carbonyl compounds with an aid of a Lewis acid; the products can be readily converted to α-methylene-γ-butyrolactones.     

Scattering of light by films having nonrandom orientation fluctuations. II

The theory for scattering of light from films in which the orientation correlation between two scattering elements depends upon the angle β between the optic axes and the vector connecting the two elements is extended. A delta-function type dependence is assumed in which the correlation is strongest when β equals some preferred value β₀. Calculated results of scattered intensities are shown to be similar to experimental observations.     

Switching extended 1,3-diequatorial and bent 1,3-diaxial states of a disubstituted hinge sugar by ligand exchange reactions on Pt(II)

The bent conformation of a trisaccharide containing 2,4-diaminoxylopyranoside, in which both end sugars are presented in 1,3-diaxial orientation, is fixed by chelation of the diamino groups to Pt(II) and unfixed by a ligand exchange reaction with NaCN or thiourea giving its extended conformation.     

Cationic oligomerization of bicyclic oxalactam

Cationic oligomerization of bicyclic oxalactam, 8-oxa-6-azabicyclo[3.2.1]octan-7-one [abbreviated as BOL ( 1 )], was carried out at 0–60°C with trifluoromethanesulfonic acid and borontrifluoride etherate as catalysts to obtain the oligomer mixture at high yield. From the structural analysis of the isolated dimer, a N-(2(e)-carbamoyltetrahydropyran-6(e)-yl)-8-oxa-6-azabicyclo[3.2.1]octan-7-one, the oligomerization proceeded through the ⁵C-⁶N scission in ( 1 ) but not through the ⁶N-⁷C (amide group) scission as generally observed in common lactams. This peculiar oligomerization must result from the protonation to the oxamide unit in the BOL molecule.