In 2019,Journal of the American Chemical Society included an article by Chen, Xiao-Wang; Zhu, Lei; Gui, Yong-Yuan; Jing, Ke; Jiang, Yuan-Xu; Bo, Zhi-Yu; Lan, Yu; Li, Jing; Yu, Da-Gang. Quality Control of Methyltriphenylphosphonium bromide. The article was titled 《Highly Selective and Catalytic Generation of Acyclic Quaternary Carbon Stereocenters via Functionalization of 1,3-Dienes with CO2》. The information in the text is summarized as follows:
A highly selective copper-catalyzed generation of chiral all-carbon acyclic quaternary stereocenters via functionalization of 1,3-dienes with CO2 is reported. A variety of readily available 1,1-disubstituted 1,3-dienes, as well as a 1,3,5-triene, undergo reductive hydroxymethylation with high chemo-, regio-, E/Z-, and enantioselectivities. The reported method features good functional group tolerance, is readily scaled up to at least 5 mmol of starting diene, and generates chiral products that are useful building blocks for further derivatization. Systemic mechanistic investigations using d. functional theory calculations were performed and provided the first theor. investigation for an asym. transformation involving CO2. These computational results indicate that the 1,2-hydrocupration of 1,3-diene proceeds with high π-facial selectivity to generate an (S)-allylcopper intermediate, which further induces the chirality of the quaternary carbon center in the final product. The 1,4-addition of an internal allylcopper complex, which differs from previous reports involving terminal allylmetallic intermediates, to CO2 kinetically determines the E/Z- and regioselectivity. The rapid reduction of a copper carboxylate intermediate to the corresponding silyl-ether in the presence of Me(MeO)2SiH provides the exergonic impetus and leads to chemoselective hydroxymethylation rather than carboxylation. These results provide new insights for guiding further development of asym. C-C bond formations with CO2. After reading the article, we found that the author used Methyltriphenylphosphonium bromide(cas: 1779-49-3Quality Control of Methyltriphenylphosphonium bromide)
Methyltriphenylphosphonium bromide(cas: 1779-49-3) is an organophosphorus compound, with potential use as a precursor and a solvent in organic synthesis. And it is used widely for methylenation via the Wittig reaction.Quality Control of Methyltriphenylphosphonium bromide
Referemce:
Bromide – Wikipedia,
bromide – Wiktionary