Discrete <i>O</i>-Lactate and β-Alkoxybutyrate Aluminum Pyridine–Bis(naphtholate) Complexes: Models for Mechanistic Investigations in the Ring-Opening Polymerization of Lactides and β-Lactones
作者:Joice S. Klitzke、Thierry Roisnel、Evgeny Kirillov、Osvaldo de L. Casagrande、Jean-François Carpentier
DOI:10.1021/om401214q
日期:2014.10.27
Methyl aluminum(III) complexes ONOSiR3}AlMe (SiR3 = SiPh3 (2a), SiMe2tBu (2b)) were synthesized by reaction of AlMe3 with pyridine–bis(naphthol) proligands ONOSiR3}H2 (1a,b) having bulky o-SiR3 substituents on the naphthol groups. Complexes 2a,b were converted into the Al isopropoxide, O-lactate, and β-alkoxybutyrate complexes ONOSiR3}AlOR′ (R′ = iPr (3a), (S)-CH(Me)CO2iPr (4a,b), (R)-CH(Me)CH2CO2Me
甲基铝(III)络合物ONO SIR3 }阿尔梅(SIR 3 = SIPH 3(图2a),森2吨BU(图2b))通过阿尔梅的反应合成3用吡啶-双(萘酚)前配体ONO SIR3 }ħ 2(1a,b)在萘酚基团上具有庞大的o- SiR 3取代基。络合物图2a,b被转换成铝,异丙醇Ó乳酸盐,和β-alkoxybutyrate络合物ONO SIR3 }阿洛'(R'=我PR(3a),(S)-CH(Me)CO 2 i Pr(4a,b),(R)-CH(Me)CH 2 CO 2 Me(5a),rac -CH(CF 3)CH 2 CO 2 Et (6a))通过与相应的醇以及α-和β-羟基酯R'OH反应。X射线衍射研究表明,SiPh 3苯基与次甲基,亚甲基和烷基酯基团的氢之间存在C– H ···π紧密接触(对于2a和4a – 6a))并通过溶液NMR进行分析。与(S)-4b的情况相反,在20°C下,(S)-4a与外消旋丙交酯(rac