first-order kinetics and seems to be mainly an enthalpic process with a small negative activation entropy, as revealed by polarimetric measurements at low temperatures. This is in accordance with Cα–S bondrotation as the rate-determining step. The salts [R1C(R2)SO2tBu]Li have half-lives of racemization in the order of several hours at –105 °C. The deuteriation of the salts at –105 °C with CF3CO2D
PTAB mediated open air synthesis of sulfonamides, thiosulfonates and symmetrical disulfanes
作者:Debayan Sarkar、Manoj Kumar Ghosh、Nilendri Rout
DOI:10.1016/j.tetlet.2018.05.017
日期:2018.6
A facile methodology has been described which has successfully simplified the generation of sulfonamides, thiosulfonates and symmetric disulfanes. This “trio” of reactions occur in an open air metal free atmosphere and has also been scaled up to grams making it suitable for commercialization. The reactions also have been successfully carried out with asymmetric variants, thus contributing to the chiral
Photo-induced synthesis of β-sulfonyl imides from carboxylic acids
作者:Linwei Zeng、Jian Jin、Jixiao He、Sunliang Cui
DOI:10.1039/d1cc02559g
日期:——
A photo-induced imidation process of carboxylic acids is described. Numerous carboxylic acids could convert to β-sulfonyl imides in the presence of N-sulfonyl ynamides under visible light irradiation. Control experiments and mechanistic studies demonstrate that this imidation process involves a hydroacyloxylation/radical rearrangement cascade. This protocol represents a direct imidation method from
Asymmetric Transfer Hydrogenation of Ketimines Using Well-Defined Iron(II)-Based Precatalysts Containing a PNNP Ligand
作者:Alexandre A. Mikhailine、Mazharul I. Maishan、Robert H. Morris
DOI:10.1021/ol302079q
日期:2012.9.7
complexes containing PNNP ligands catalyze a highly enantioselective reduction of N-(diphenylphosphinoyl)- and N-(p-tolylsulphonyl)-ketimines. Under mild conditions and low catalyst loading, the ketimines are successfully reduced to the corresponding amines in enantiomeric excess ranging from 94 to 99%.
Highly enantioselective Rh-catalyzed transfer hydrogenation of N-sulfonyl ketimines
作者:Se Hun Kwak、Sun Ah Lee、Kee-In Lee
DOI:10.1016/j.tetasy.2010.04.047
日期:2010.4
species comprising N-sulfinyl and N-sulfonyl ketimine, oxime, and enamine derivatives were subjected to asymmetric transferhydrogenation in an azeotropic mixture of formic acid/triethylamine. Among them, the Rh-catalyzed transferhydrogenation of N-sulfonyl ketimine afforded the corresponding 1-arylalkylamines in excellent yield and with high enantioselectivity.