The direct catalytic asymmetric aldolreaction offers efficient access to β‐hydroxy carbonyl entities. Described is a robust direct catalytic asymmetric aldolreaction of α‐sulfanyl 7‐azaindolinylamide, thus affording both aromatic and aliphatic β‐hydroxy amides with high ee values. The design of this transformation features a cooperative interplay of a soft and a hard Lewisacid, which together facilitate
Thermochemical investigation of the oxygenation of vitamin K
作者:Robert A. Flowers、Sriram Naganathan、Paul Dowd、Edward M. Arnett、Seung Wook Ham
DOI:10.1021/ja00074a006
日期:1993.10
oxygen with the potassium salt derived from deprotonation of the hydroquinone form of vitaminK. From that value (-33.52±0.60 kcal/mol), the heat of deprotonation of vitamin KH 2 (-30.03±1.20 kcal/mol), and the heat of deprotonation of water (-6.05±0.3 kcal/mol), the enthalpy change for converting vitamin KH 2 to vitaminK oxide is established to be -57.5 kcal/mol, in reasonable agreement with our previous
Direct Catalytic Asymmetric Addition of Allyl Cyanide to Ketones via Soft Lewis Acid/Hard Brønsted Base/Hard Lewis Base Catalysis
作者:Ryo Yazaki、Naoya Kumagai、Masakatsu Shibasaki
DOI:10.1021/ja101687p
日期:2010.4.21
step. A ternary catalytic system comprising a soft Lewis acid/hard Brønstedbase and an additional hard Lewisbase, in which the basicity of the hard Brønstedbase Li(OC(6)H(4)-p-OMe) was enhanced by phosphine oxide (the hard Lewisbase) through a hard-hard interaction, outperformed the previously developed binary soft Lewis acid/hard Brønstedbase catalytic system, leading to higher yields and enantioselectivities
Copper-Catalyzed Electrochemical Selective B–H Oxygenation of <i>o</i>-Carboranes at Room Temperature
作者:Yik Ki Au、Hairong Lyu、Yangjian Quan、Zuowei Xie
DOI:10.1021/jacs.0c02490
日期:2020.4.15
Copper-catalyzed electrochemical selective cage B-H oxygenation of o-carboranes has been achieved for the first time. Under constant electric current (4.0 mA) at room temperature, copper-catalyzed cross-coupling of carboranyl amides with lithium phenolates results in the formation of B(4,5)-diphenolated-o-carboranes via direct B-H activation, whereas the use of lithium tert-butoxide affords B(4)-monooxygenated
Stereoselective synthesis of 2-aryloxy acids from lactamide derived esters of racemic α-halo carboxylic acids
作者:Paul N Devine、Ulf -H Dolling、Richard M Heid、David M Tschaen
DOI:10.1016/0040-4039(96)00391-7
日期:1996.4
Pyrrolidine derived (S)-lactamide auxiliaries mediate a highly stereoselective coupling reaction between racemic α-haloacids and aryloxides. These amide auxiliaries exhibit enhanced rates of reaction as well as increased degrees of diastereoselection over conventional ester auxiliaries.