Outer-Sphere Control for Divergent Multicatalysis with Common Catalytic Moieties
摘要:
We herein report two examples of one-pot, simultaneous reactions, mediated by multiple, orthogonal catalysts with the same catalytic motif. First, BINOL-derived chiral phosphoric acids (CPA) and phosphothreonine (pThr)-embedded peptides were found to be matched for two different steps in double reductions of bisquinolines. Next, two pi-methylhistidine (Pmh)-containing peptides catalyzed enantio-and chemoselective acylations and phosphorylations of multiple substrates in one pot. The selectivity exhibited by common reactive moieties is adjusted solely by the appended chiral scaffold through outer-sphere interactions.
Hydrolysis of toxic organophosphorus compounds by o-iodosobenzoic acid and its derivatives
作者:Philip S. Hammond、Jeffry S. Forster、Claire N. Lieske、H. Dupont Durst
DOI:10.1021/ja00202a029
日期:1989.9
Hydrolyse des esters trimethyl-1,2,2 propyle et isopropyle de l'acide methyl phosphonofluoridique (soman et sarin respectivement), du N,N-dimethyl phosphoramidocyanidate d'ethyle (tabum) et du (diethyl nitro-4 phenyl) phosphate dans des solutions aqueuses micellaires de chlorure de (palmityl trimethyl) ammonium, en presence d'acide iodosyl-«2» benzoique
水解酯三甲基-1,2,2 丙基和异丙基甲基磷酰氟(soman 和 sarin 相关),du N,N-二甲基磷酰胺氰化物 d'ethyle (tabum) et du (diethyl nitro-4 phenyl) 磷酸 dans dessolutions aqueuses micelliaires de chlorure de (palmityl trimethyl) 铵, en d'acide iodosyl-«2»benzoique
Phosphomonoesters and phosphodiesters derived from the photohydrolysis of 2-methoxy-5-nitrophenyl substituted phosphotriesters
作者:Nilsa R. Graciani、Daniel S. Swanson、Jeffery W. Kelly
DOI:10.1016/0040-4020(94)01012-o
日期:1995.1
Phosphotriesters composed of one or two 2-methoxy-5-nitrophenyl group(s) can be quantitatively photohydrolyzed in aqueous acetonitrile to yield the desired phosphodiester or phosphomonoester, respectively. Photohydrolysis occurs by attack of hydroxide at both the phosphoryl phosphorus and at the ipso-carbon in the triplet exited state of the 2-methoxy-5-nitrophenyl substituted phosphoesters. The photophysical studies
Reinvestigation of the 31P NMR evidence for the formation of diorganyl phosphoropyridinium intermediates
作者:Johan Nilsson、Adam Kraszewski、Jacek Stawinski
DOI:10.1039/b107792a
日期:2001.11.29
A 31P NMR study on the reactions of diphenyl and diethyl chlorophosphates/bromophosphates with pyridine showed that equilibria of these reactions are heavily shifted to the left and thus concentrations of the putative diorganyl phosphoropyridinium chlorides/bromides are usually below the detection level of this spectroscopic method. However, when diphenyl iodophosphate was subjected to reaction with pyridine, we were able for the first time to observe the formation of a diorganyl phosphoropyridinium intermediate by 31P NMR spectroscopy.
Laser Flash Photolysis Kinetic Studies of Enol Ether Radical Cations. Rate Constants for Heterolysis of α-Methoxy-β-phosphatoxyalkyl Radicals and for Cyclizations of Enol Ether Radical Cations
作者:John H. Horner、Elsa Taxil、Martin Newcomb
DOI:10.1021/ja0177399
日期:2002.5.1
described. Cyclizations of enol ether radical cations 1 gave distonic radical cations containing the diphenylalkyl radical, whereas cyclizations of enol ether radical cations 2 gave distonic radical cation products containing a diphenylcyclopropylcarbinyl radical moiety that rapidly ring-opened to a diphenylalkyl radical product. For 5-exo cyclizations, the heterolysis reactions were rate limiting, whereas
Kinetics of Radical Heterolysis Reactions Forming Alkene Radical Cations
作者:John H. Horner、Laurent Bagnol、Martin Newcomb
DOI:10.1021/ja046089g
日期:2004.11.1
pseudo-first-order rateconstant of k = 1 x 10(6) s(-1) and is trapped by methanol in acetonitrile in a reversible reaction. The 1,1-dimethyl-2-(diphenylphosphatoxy)hexyl radical (4b) heterolyzes in acetonitrile to give radical cation 6 in an ion pair with a rateconstant of k(het) = 4 x 10(6) s(-1), and the ion pair collapses with a rateconstant of k < or = 1 x 10(9) s(-1). Rateconstants for heterolysis
β-(酯) 烷基自由基异裂的速率常数由直接激光闪光光解研究和间接动力学研究的组合确定。1,1-二甲基-2-甲磺酰氧基己基自由基 (4a) 在乙腈中在室温下以 k(het) > 5 x 10(9) s(-1) 的速率常数断裂,从 2-甲基得到自由基阳离子-2-庚烯 (6),它与乙腈以 k = 1 x 10(6) s(-1) 的伪一级速率常数反应,并在可逆反应中被乙腈中的甲醇捕获。1,1-二甲基-2-(二苯基磷酸酯氧基)己基 (4b) 在乙腈中杂解,生成离子对中的自由基阳离子 6,速率常数为 k(het) = 4 x 10(6) s(-1) ,并且离子对以 k < 或 = 1 x 10(9) s(-1) 的速率常数坍塌。1,1-二甲基-2-(2, 2-二苯基环丙基)-2-(二苯基磷酸酯氧基)乙基(5a)和1,1-二甲基-2-(2,2-二苯基环丙基)-2-(三氟乙酰氧基)乙基(5b)在各种溶剂中进行了测量,并且确定了