Structural Diversity of Lithium N ‐Mesityl‐ P , P ‐diphenylphosphinimidate of the type [(L)Li{O−PPh 2 =N−Mes] n Depending on Lewis Base L

Abstract Metalation of N ‐mesityl‐ P,P ‐diphenylphosphinic amide with n BuLi in toluene yields tetranuclear lithium N ‐mesityl‐ P , P ‐diphenylphosphinimidate ([Ph 2 P(OLi)=N−Mes] 4 , 1 ). Metalation of Ph 2 P(O)−N(H)Mes with a mixture of dibutylmagnesium and butyllithium in DME leads to formation of dinuclear [Ph 2 P{OLi(dme)}=N−Mes] 2 ( 2 ). Excess of Ph 2 P(O)−N(H)Mes gives dinuclear [Li(O−PPh 2 =N−Mes){Ph 2 P(=O)−N(H)−Mes}] 2 ( 3 ) with three‐coordinate alkali ions. The metathetical approach via reaction of 1 with anhydrous magnesium bromide in ethereal solution yields [{(thf)LiBr} 2 {(thf)Li(O−PPh 2 =NMes)(Et 2 O)Li(O−PPh 2 =NMes)}] ( 4 ). Heterobimetallic Li/Mg compounds are not accessible by these protocols. Reactions of 1 with DME, with excess of Ph 2 P(O)−N(H)Mes or with LiBr allows the straightforward conversion to compounds 2 , 3 and 4 .imag

Aves que nidificam em cavidades na Reserva Natural Salto Morato - Guaraqueçaba (PR) /

Orientador : James Joseph RoperDissertaçăo (mestrado) - Universidade Federal do Paraná, Setor de Cięncias Biológicas, Programa de Pós-Graduaçăo em Ecologia e Conservaçao. Defesa: Curitiba, 2007Inclui bibliografi

Potassium Dimesitylphosphinite Catalyzed Intermolecular Hydrophosphorylation of Alkynes

In this investigation we evaluated the scope of the intermolecular hydrophosphorylation (Pudovik reaction) of alkynes R¹–CC–R² (R¹ = H, alkyl, Ph; R² = alkyl, Ph, COOMe, SiMe₃, Si­(<i>i</i>Pr)₃) with bis­(2,4,6-trimethylphenyl)­phosphane oxide (dimesitylphosphane oxide, Mes₂P­(O)­H) in tetrahydrofuran at room temperature or 65 °C, catalyzed with 5 or 10 mol % of potassium dimesitylphosphinite (Mes₂P–O–K), yielding alkenyldimesitylphosphane oxides (Mes₂P­(O)–C­(R¹)C­(H)­R²). This procedure requires substituents with a −I effect at the CC triple bond, whereas alkyl-substituted alkynes are inactive under these reaction conditions. The hydrophosphorylation proceeds regioselectively, but <i>E</i>/<i>Z</i> isomer mixtures are obtained. <i>E</i>/<i>Z</i> isomerization occurs at elevated temperatures with an estimated energy barrier of 59 kJ mol^–1 (R¹ = Me; R² = Ph). Trimethylsilyl substituents at the alkyne functionality (R¹ = H, <i>n</i>Bu; R² = SiMe₃) destabilize the product, leading to degradation and formation of Mes₂P–O–SiMe₃ and R¹–CC–H