203866-88-0Relevant articles and documents
A relative organolithium stability scale derived from tin-lithium exchange equilibria. Substituent effects on the stability of α-oxy- and α-aminoorganolithium compounds
Grana, Paula,Paleo, M. Rita,Sardina, F. Javier
, p. 12511 - 12514 (2002)
Quantitative thermodynamic stability scales of organolithium compounds can be derived from measurements of tin-lithium exchange equilibria. A ΔGeq scale of α-oxy- and α-aminoorganolithium compounds was established, and quantitative stabilization effects of O-alkyl, O-alkoxyalkyl, O-carbamoyl, N-carbamoyl, and O-carbonyl groups of the α-carbanion are presented. It has been found that an α-oxycarbanion is far better stabilized by a carbonyl group as the O-substituent than by an alkyl or alkoxyalkyl group, while the anion-stabilizing effects of the different O-carbonyl substituents are comparable. An N-carbamoyl group was found to have a somewhat higher stabilizing effect than its O-carbamoyl counterpart. NMR data are presented that show that benzylic N- or O-substituted carbanions have highly planarized structures where the negative charge is highly delocalized. The stability data obtained from the tin-lithium exchanges can be easily converted into "effective pK" data that are useful for predicting the acid-base behavior of this type of organolithium species.
Copper nanoparticles catalyzed N-H functionalization: An efficient solvent-free N-tert-butyloxycarbonylation strategy
Deb, Barnali,Debnath, Sudipto,Deb, Anindita,Maiti, Dilip K.,Majumdar, Swapan
supporting information, p. 629 - 633 (2017/01/25)
A chemoselective transformation of amines to their tert-butyloxycarbonyl (Boc) protected derivatives (NBoc) is described using Cu-NPs under solvent-free conditions. Simple method, rapid reaction rate, mild conditions, tolerance of a wide range of functional groups, excellent yield, ease recovery and high catalytic turnover are the salient features of this approach. tert-Butyloxycarbonylation of chiral amino acid esters and amino alcohols were performed without racemization.
1,3-Disulfonic acid imidazolium hydrogen sulfate as an efficient and reusable ionic liquid catalyst for the N-Boc protection of amines
Shirini, Farhad,Khaligh, Nader Ghaffari
, p. 386 - 393 (2013/03/14)
1,3-Disulfonic acid imidazolium hydrogen sulfate is easily prepared and used as an efficient and recyclable ionic liquid for the N-Boc protection of amines at room temperature and neat conditions. This new method consistently has the advantages of excellent yields and short reaction times. Further, the catalyst can be reused and recovered for several times without loss of activity.
