Unusual reaction behavior of gem-difluorocyclopropane derivatives: stereoselective synthesis of ß-monofluoroallylic alcohols, ethers, esters, and amide.

On treating gem-difluorocyclopropylstannanes, derived from the radical hydrostannation of gem-difluorocyclopropenes, with 1.5 equiv of MeLi in THF at -78 °C for 5 min, followed by quenching the reaction with various agents, such as H2O, alcohols, carboxylic acids, and tosylamide, the corresponding ß-fluoroallylic alcohols, ethers, esters, and amide were obtained with exclusive Z-selectivity in acceptable yields.

Stereocontrolled generation of nucleophilic (Z)- or (E)-α-fluoroalkenylchromium reagents via carbon-fluorine bond activation: highly stereoselective synthesis of (E)- or (Z)-ß-fluoroallylic alcohols.

Highly nucleophilic (Z)- or (E)-α-fluoroalkenylchromium species could be generated in a stereoselective manner via C-F bond activation of CBrF2-containing molecules, and they reacted smoothly with various aldehydes to give (E)- or (Z)-ß-fluoroallylic alcohol derivatives in high yields, respectively.

Aggressive carcinoid tumors arising in the duodenum, ileum, and rectum with liver metastasis: a report of three cases.

Three aggressive carcinoid tumors with liver metastasis arising in the duodenum (Case 1, 72-year-old man), ileum (Case 2, 72-year-old man), and rectum (Case 3, 67-year-old woman) were studied. Case 1 initially suffered from hemorrhage from an exophytic large tumor and developed a liver metastasis after operation. Cases 2 and 3 first presented as multiple liver metastases. Case 3 had a small submucosal tumor and showed a relatively high cell proliferation activity. Neoplastic cells expressed gastrin in Case 1, serotonin in Case 2, and did not express several peptides in Case 3.

Stereocontrolled synthesis of beta-difluoromethylated materials.

Investigation of synthetic routes for regio- and stereocontrolled fluorinated materials with a difluoromethyl group, using ethyl bromodifluoroacetate as a starting material, is described. In particular, (E)-difluoromethylated trisubstituted olefins were prepared via the proton migration reaction catalyzed by using fluoride anion. Further, optically active beta-difluoromethyl esters were obtained by the enzymatic resolution.

Template-assisted stereoselective photocyclodimerization of 2-anthracenecarboxylic acid by bispyridinio-appended gamma-cyclodextrin.

[reaction: see text] Four kinds of bispyridinio-appended gamma-cyclodextrin (gamma-CD) were prepared to make a molecular flask for controlling the stereoselectivity of photocyclodimerization of 2-anthracenecarboxylate. When the photocyclodimerization of 2-anthracenecarboxylate was carried out in the presence of A,E-bispyridinio-appended gamma-CD, the relative yield of one of the configurational isomers, the head-to-head/anti-isomer, was increased 1.8-fold compared to the corresponding yield in the presence of unmodified gamma-CD or in the absence of any gamma-CD. The optical yields of the photocyclodimerization reaction products also increased more than 10-fold by the addition of bispyridinio-appended gamma-CD compared with unmodified gamma-CD.