Asymmetric Hydrovinylation of 1-Vinylcycloalkenes. Reagent Control of Regio- and Stereoselectivity

Asymmetric hydrovinylation of 1-vinylcycloalkenes. Reagent control of regio- and stereoselectivity.

1-Vinylcycloalkenes undergo highly regio- and enantioselective (>98% ee) 1,4-hydrovinylation (HV) when treated with ethylene (1 atm) at room temperature in the presence of [(S,S)-2,4-bis-diphenylphosphinopentane (BDPP)]CoCl(2) (0.05 equiv) and methylaluminoxane. The minor 1,2-HV products, seen only in 1-vinylcyclohexene (~15%) and 1-vinylcycloheptene (2%), are formed as racemic mixtures. The co...

Studies of Regio- and Stereoselectivity

Asymmetric hydrovinylation reaction.

Carbon-carbon bond-forming reactions are among the most important types of bond constructions in organic chemistry. Yet, the paucity of methods for the stereoselective incorporation of abundantly available carbon feedstocks such as CO, CO2, HCN, or simple olefins to prochiral substrates is one of the major limitations in this area.1 Ideally, from a manufacturing perspective, these reactions sho...

Cobalt-catalysed asymmetric hydrovinylation of 1,3-dienes

In the presence of bidentate 1,n-bis-diphenylphosphinoalkane-CoCl2 complexes {Cl2Co[P P]} and Me3Al or methylaluminoxane, acyclic (E)-1,3-dienes react with ethylene (1 atmosphere) to give excellent yields of hydrovinylation products. The regioselectivity (1,4or 1,2-addition) and the alkene configuration (Eor Z-) of the resulting product depend on the nature of the ligand and temperature at whic...

the relationship between locus of control, efl reading and writing achievement, and use of language learning strategies

تاثیر منبع کنترل رفتار بر روی موفقیت تحصیلی زبان آموزان انگلیسی بندرت در ایران ارزیابی شده است. هدف این تحقیق ارزیابی رابطه بین منبع کنترل رفتار زبان آموزان انگلیسی و موفقیت آنها در مهارت های خواندن و نوشتن زبان انگلیسی است. محقق همچنین رابطه بین منبع کنترل رفتار و راهبردهای یادگیری زبان انگلیسی را در این تحقیق جستجو می کند. بدین منظور محقق ابتدا نسخه فارسی پرسشنامه منبع کنترل رفتار (duttweiler...