نتایج جستجو برای: cope rearrangement

تعداد نتایج: 59498  

Journal: :Angewandte Chemie 2004
Dorothea Fiedler Robert G Bergman Kenneth N Raymond

Chemists have long envied the ability of enzymes to manipulate reaction energetics and specificity through steric confinement and precise functional-group interactions. The enormous rate accelerations that enzymes achieve at modest temperatures may be attributed to their high degree of complexity, and the synthetic chemist is hard pressed to create such well-constructed catalytic scaffolds. Yet...

Journal: :The journal of physical chemistry. A 2012
A Chenel G Dive C Meier M Desouter-Lecomte

In this work, we present optimal control calculations in a dissipative environment. To this end, the auxiliary density matrix method describing the dissipative quantum dynamics is combined with optimal control theory. The resulting approach, which is nonperturbative in the laser-system interaction, is applied to model the control of Cope's isomerization of the methyl-cyclopentadienylcarboxylate...

Journal: :The journal of physical chemistry. A 2013
Inbal Tuvi-Arad Tamás Rozgonyi András Stirling

Many reactions feature symmetry variation along the reaction path on the potential energy surface. The interconversion of the point group symmetry of the stationary points can be characteristic of these processes. Increasing the temperature, however, leads to the loss of symmetry in its traditional yes-no language. We find that in such cases the instantaneous distance of the molecular structure...

Journal: :Organic letters 2013
Hong Ren William D Wulff

The catalytic asymmetric aminoallylation of chiral aldehydes is developed as a new method for the catalyst controlled synthesis of syn- and anti-1,3-aminoalcohols. This methodology is highlighted in the synthesis of the sedum alkaloids (+)-sedridine and (+)-allosedridine both of which have their final carbon incorporated during closure of the piperidine ring via a hydroformylation with formalde...

2002
Holger Butenschön

Tricarbonylchromium complexes of benzocyclobutenone, benzocyclobutenedione, and 1,3-indandione are readily prepared by hydrolysis of the complexes of the corresponding acetals. Reduction of the benzocyclobutenone complex gives rise to an oxyanion-driven ring opening to the corresponding ortho-quinodimethane intermediate, which can be trapped with dienophiles. Addition of 1-ethoxy-1-lithioethene...

Journal: :Organic & biomolecular chemistry 2003
Lisbet Kvaernø Per-Ola Norrby David Tanner

A vinylsilane-ketiminium ion cyclization involving iminium species derived from amines 6 and 7 was investigated experimentally as a possible approach to some biologically interesting 1-azaspirocycles. However, even under conditions of microwave irradiation at high temperatures no such cyclization was observed whereas (in line with previous results) the corresponding vinylsilane-aldiminium ion c...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید