Dimethylmalonyltrialkylphosphoranes: New General Reagents for Esterification Reactions Allowing Controlled Inversion or Retention of Configuration on Chiral Alcohols
作者:James McNulty、Alfredo Capretta、Vladimir Laritchev、Jeff Dyck、Al J. Robertson
DOI:10.1021/jo026639y
日期:2003.2.1
through reaction of a trialkylphosphine with 2-chlorodimethylmalonate in the presence of triethylamine. These new reagents promote the condensation reaction of carboxylic acids with alcohols to provide esters along with trialkylphosphine oxide and dimethylmalonate. The condensation reaction of chiral secondary alcohols can be controlled to give either high levels of inversion or retention through a
The presence of an event in the narrated situation affects its availability to the comprehender
作者:Rolf A. Zwaan、Carol J. Madden、Shannon N. Whitten
DOI:10.3758/bf03209350
日期:2000.11
Narrative descriptions of events often depart from how these events would have occurred in "real time." For example, narratives often contain time shifts in which events that are irrelevant to the plot are omitted. Zwaan (1996) has shown that these time shifts may affect on-line comprehension. Specifically, they are associated with increases in processing load and a deactivation of previous information. The experiments in the present article show that the situation is more complex. Specifically there is only a deactivation of previous events if they are not assumed to be ongoing after a time shift. Furthermore, explicit discontinuations of events, as in he stopped walking also lead to deactivations when compared with explicit continuations and resumptions.
Stereochemie von Metallocenen, 8. Mitt.: Die Absolute Konfiguration von Optisch Aktiven Benzol-chromtricarbonyl-derivaten; Asymmetrische Synthese und Kinetische Racematspaltung von Chiralen Metallocenen