Organozinc Generation via the Titanium-Catalyzed Activation of Alkyl Halides
作者:Lauren M. Fleury、Brandon L. Ashfeld
DOI:10.1021/ol902374v
日期:2009.12.17
A protocol for the generation of organozinc reagents via catalytic activation of alkyl halides is described herein. Subsequent nucleophilic addition to carbonyl derivatives provided the desired products in good to excellent yields (76-99%). Evidence suggests that titanocene dichloride catalyzes the formation of an organozinc species. This discovery will have wide ranging applicability in the generation of highly reactive organometallic reagents.
First Studies of the Transition Metal-Catalyzed [5+2] Cycloadditions of Alkenes and Vinylcyclopropanes: Scope and Stereochemistry
作者:Paul A. Wender、Craig O. Husfeld、Elke Langkopf、Jennifer A. Love
DOI:10.1021/ja973650k
日期:1998.3.1
Cooperative Titanocene and Phosphine Catalysis: Accelerated C–X Activation for the Generation of Reactive Organometallics
作者:Lauren M. Fleury、Andrew D. Kosal、James T. Masters、Brandon L. Ashfeld
DOI:10.1021/jo301726v
日期:2013.1.18
transmetalation approach toward the generation of Grignard and organozinc reagents mediated by a titanocene catalyst. This method enables the metalation of functionalized substrates without loss of functional group compatibility. Allyl zinc reagents and allyl, vinyl, and alkyl Grignard reagents were generated in situ and used in the addition to carbonyl substrates to provide the corresponding carbinols in yields
Easy to scale: A rhodium‐catalyzed asymmetric intramolecular [5+2] cycloaddition of alkyne–vinylcyclopropanes has been developed. High enantioselectivities of up to >99.5 % ee have been achieved by the use of a chiral phosphoramidite ligand. The reaction can be easily scaled up and the stereochemical model of the present catalysis has also been proposed.