Stereocontrol in radical processes through the exocyclic effect: dual role of triethylboron as radical initiator and in situ derivatization agent.

[structure in text] The diastereoselectivity of radical processes involving 1,3-diols is increased significantly with a simple and efficient strategy using the exocyclic effect. Boronate derivatives are successfully formed in situ by treatment of an equimolar amount of Et(3)B in the presence of oxygen. This step is followed by the mediation of a carbon-centered radical alpha to the cyclic boronate to give the anti reduced product with high stereocontrol. The sequence is also extended to beta-amino alcohols.

[Tomodensitometry in osteoarticular pathology. Preliminary results]. / La tomodensitométrie en pathologie ostéo-articulaire: Premiers résultats.

From the investigation of 180 patients, the preliminary results of tomo-densitometric study ("scanning") of the locomotor system are presented. The technique permits investigation in the transverse spatial plane, which is ignored in conventional radiology. We feel this to be a major advantage in osteo-articular disease, especially for the spine (measurement of the diameter of the canal, analysis of the posterior structures), the sacro-iliac joints, hip joints (easy-measurement of the angles of anteversion) and patello-femoral joints. The densitometric measurement is the second advantage. It allows the estimation of the degree of bony calcification of any bone in the body with great precision. The preliminary study already demonstrates the limitations of the technique (exploration of a single transverse plane, edge effect, and necessity for a new anatomy).