1795-80-8Relevant articles and documents
The Chemistry of Acylgermanes: Triacylgermenolates Represent Valuable Building Blocks for the Synthesis of a Variety of Germanium-Based Photoinitiators
Fischer, Roland C.,Frühwirt, Philipp,Gescheidt, Georg,Griesser, Thomas,Haas, Michael,Kelterer, Anne-Marie,Knoechl, Andreas,Müller, Stefanie M.,Moszner, Norbert,Pillinger, Michael,Radebner, Judith,Torvisco, Ana,Wasdin, Perry T.
, p. 15204 - 15217 (2020)
The formation of a stable triacylgermenolate 2 as a decisive intermediate was achieved by using three pathways. The first two methods involve the reaction of KOtBu or alternatively potassium with tetraacylgermane 1 yielding 2 via one electron transfer. The mechanism involves the formation of radical anions (shown by EPR). This reaction is highly efficient and selective. The third method is a classical salt metathesis reaction toward 2 in nearly quantitative yield. The formation of 2 was confirmed by NMR spectroscopy, UV-vis measurements, and X-ray crystallography. Germenolate 2 serves as a starting point for a wide variety of organo-germanium compounds. We demonstrate the potential of this intermediate by introducing new types of Ge-based photoinitiators 4b-4f. The UV-vis absorption spectra of 4b-4f show considerably increased band intensities due to the presence of eight or more chromophores. Moreover, compounds 4d-4f show absorption tailing up to 525 nm. The performance of these photoinitiators is demonstrated by spectroscopy (time-resolved EPR, laser flash photolysis (LFP), photobleaching (UV-vis)) and photopolymerization experiments (photo-DSC measurements).
Direct conversion of N -alkoxyamides to carboxylic esters through tandem nbs-mediated oxidative homocoupling and thermal denitrogenation
Zhang, Ningning,Yang, Rui,Zhang-Negrerie, Daisy,Du, Yunfei,Zhao, Kang
, p. 8705 - 8711 (2013/09/24)
Treatment of N-alkoxyamides with NBS in toluene was found to conveniently afford the corresponding carboxylic esters, including those bearing a bulky or long-chain substituent, in satisfactory to excellent yields. This approach not only represents a convenient and economic approach to a direct transformation of an alkoxyamide moiety into the carboxylic ester functional group, via oxidative homocoupling and the subsequent thermal denitrogenation, but also facilitates the synthesis of sterically hindered carboxylic esters.
Activated Basic Alumina Promotes a Mild, Clean and High-Yield Racemization-Free Synthesis of t-Butyl Esters from Chiral Acid Bromides and t-Butyl Alcohol
Nagasawa, Kazuo,Ohhashi, Keiko,Yamashita, Asami,Ito, Keiichi
, p. 209 - 212 (2007/10/02)
Esterification of a variety of acid bromides having even steric bulkiness with t-BuOH/activated basic alumina gave the corresponding t-butyl esters in good to excellent yields.In the case of chiral acid bromides, no racemization has been ascertained for the first time.