CH3 H3C. H3C H H གཡིག བཤད 1:|:ཁ ག གྱིས ས པ ཀ ཡིག རྒྱུད CH3 CH + H3C H H CH3 Monocarbonyl compounds can be alkylated at the a position via the use of lithium diisopropylamide, a strong, sterically hindered base. Because only one carbonyl group is available to participate in resonance stabilization of the enolate, the a-hydrogens are less acidic than those of ẞ-dicarbonyl compounds and so a stronger base is necessary to completely convert the compound to the enolate. The reaction occurs in a polar aprotic solvent such as THF. Compounds such as esters, ketones, and nitriles are commonly alkylated via this procedure. Aldehydes, however, rarely give high yields in this procedure because they tend to undergo carbonyl condensation instead. Draw curved arrows to show the movement of electrons in this step of the mechanism. Arrow-pushing Instructions H₂C :0: X CH3 H₂C :0: CH3 ab

CH3 H3C. H3C H H གཡིག བཤད 1:|:ཁ ག གྱིས ས པ ཀ ཡིག རྒྱུད CH3 CH + H3C H H CH3 Monocarbonyl compounds can be alkylated at the a position via the use of lithium diisopropylamide, a strong, sterically hindered base. Because only one carbonyl group is available to participate in resonance stabilization of the enolate, the a-hydrogens are less acidic than those of ẞ-dicarbonyl compounds and so a stronger base is necessary to completely convert the compound to the enolate. The reaction occurs in a polar aprotic solvent such as THF. Compounds such as esters, ketones, and nitriles are commonly alkylated via this procedure. Aldehydes, however, rarely give high yields in this procedure because they tend to undergo carbonyl condensation instead. Draw curved arrows to show the movement of electrons in this step of the mechanism. Arrow-pushing Instructions H₂C :0: X CH3 H₂C :0: CH3 ab

Organic Chemistry

8th Edition

ISBN:9781305580350

Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. Foote

Publisher:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. Foote

Chapter18: Functional Derivatives Of Carboxylic Acids

Section: Chapter Questions

Problem 18.38P: A step in a synthesis of PGE1 (prostaglandin E1, alprostadil) is the reaction of a trisubstituted...

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