Treatment of the edentulous atrophic maxilla using zygomatic implants: evaluation of survival rates over 5-10 years.

The aim of this retrospective observational cohort study was to analyse and report the 5-10-year survival rates of endosseous zygomatic implants used in the rehabilitation of the atrophic maxilla. Forty-three consecutive zygomatic implant placements in 25 patients were evaluated over a 5-10-year period. All zygomatic implant surgery was carried out under general anaesthesia.

Synthesis of the C1-C20 and C15-C27 segments of aplyronine A.

The synthesis of C1-C20 and C15-C27 segments of Aplyronine A is described. Oxidative cleavage of cyclic vinyl sulfones has been used to prepare key fragments of Aplyronine A. Key precursors are united by Horner-Wadsworth-Emmons and Julia-Kociensky olefination for the respective elaboration of the C1-C20 and C15-C27 segments.

Reagent-directed allylic quadraselection. Chemoselective anti- and syn-Lawton S(N)2' methylation of seven-membered epoxyvinylsulfones.

Methods have been developed for regio- and stereoselective 1,4-syn or 1,4-anti methylation of seven-membered epoxyvinylsulfones. 1,4-Syn addition is achieved via the combination of Me(2)Zn and catalytic Li(2)CuCl(4), a hitherto unexplored reagent combination. The complementary 1,4-anti addition relies on Cu(I) catalyzed methyl Grignard addition or (CH(3))(3)Al assisted CH(3)Cu addition.