wittig reaction造句

• Related to the Wittig reaction is the Peterson olefination.
• In terms of reactivity, it resembles the Tebbe reagent and Wittig reaction.
• In 1958, Leopold Horner published a modified Wittig reaction using phosphonate-stabilized carbanions.
• Wittig reactions are most commonly used to couple aldehydes and ketones to singly substituted phosphine ylides.
• Vedejs has put forth a theory to explain the stereoselectivity of stabilized and unstabilized Wittig reactions.
• Phosphine oxides are typically ( and appropriately ) viewed as useless by-products in the Wittig reaction.
• Because of its reliability and wide applicability, the Wittig reaction has become a standard tool for synthetic organic chemists.
• Most of his scientific work, including the development of the Wittig reaction, was performed during this time in T黚ingen.
• These compounds are used as reagents in the Wittig reaction, for instance methylenetriphenylphosphorane or Ph 3 P = CH 2.
• In contrast to phosphonium ylides used in the Wittig reaction, phosphonate-stabilized carbanions are more nucleophilic but less basic.
• Therefore like alkenes, phosphaalkenes engage in Wittig reactions, Peterson reactions, Cope rearrangements, and Diels-Alder reactions.
• Thus, Wittig reaction of 3-methyl-2-furanacetaldehyde with triphenylphosphonium isopropylide gave rosefuran in 67 % yield.
• Unlike the Wittig reaction, the Petasis reagent can react with a wide range of carbonyls, including aldehydes, ketones and esters.
• Take a look, for example at the page on the Wittig reaction that is more or less how we would like it.
• On the other hand, a prototypical Wittig reaction has especially poor atom economy ( merely 20 percent in the example shown ).
• "' Modified Wittig-Claisen tandem reaction "'is a cascade reaction that combines Wittig reaction and Claisen rearrangement together.
• Aggarwal specialises in a type of molecule called ylides, which are important to the Wittig reaction-a standard tool in organic chemistry.
• The second Wittig reaction uses a non-stabilised Wittig reagent, and as expected this gives mainly the " cis " product.
• Evidence suggests that the Wittig reaction of unbranched aldehydes under lithium-salt-free conditions do not equilibrate and are therefore under kinetic reaction control.
• The most popular use of the Wittig reaction is for the introduction of a methylene group using methylenetriphenylphosphorane ( Ph 3 P = CH 2 ).