Organic 10: Conjugation in Alkadienes & Allylic Systems Flashcards Preview

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Flashcards in Organic 10: Conjugation in Alkadienes & Allylic Systems Deck (25)
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1
Q

Allylic carbocation

A

a carbocation in which the positively charged carbon is allylic

2
Q

Allylic free radical

A

a free radical in which the unpaired electron is on an allylic carbon

3
Q

Allylic anion

A

a carbanion in which the negatively charged carbon is allylic

4
Q

Conjugated diene

A

system of the type C=C-C=C, in which 2 pairs of doubly bonded carbons are joined by a single bond; the pi electrons are delocalized over the unit of 4 consecutive sp2 hybridized carbons

5
Q

Conjugated systems

A

a structural arrangement in which electron delocalization permits 2 groups to interact so that the properties of the conjugated system are different from those of the separate groups

6
Q

Allylic

A

sp3 hybridized carbon of a C=C-C unit

7
Q

Vinylic

A

a carbon that is doubly bonded to another carbon

8
Q

Allylic rearrangement

A

reactions of allylic systems that yield products in which double-bond migration has occurred

9
Q

Alkadiene

A

a hydrocarbon that contains 2 double bonds

10
Q

Isolated diene

A

units in which 2 carbon-carbon double bond units are separated from each other by one or more sp3-hybridized carbon atoms

11
Q

Conjugated dienes

A

two carbon-carbon double bond units are connected to each other by a single bond

12
Q

Cumulated dienes

A

one carbon atom is common to 2 carbon-carbon double bonds

13
Q

Allene

A

the compound H2C=C=CH2 (1,2-propadiene)

14
Q

Delocalization energy

A

increased stability due to conjugation; AKA resonance energy or conjugation energy

15
Q

Elastomers

A

a synthetic polymer that possesses elasticity

16
Q

Copolymer

A

polymer assembled from 2 or more different polymers

17
Q

1, 2 Addition (Direct Addition)

A

addition of reagents of the type X-Y to conjugated dienes in which X & Y add to adjacent doubly bonded carbons

18
Q

1, 4 Addition (Conjugate Addition)

A

addition reaction in which the reagent adds to the termini of the conjugated system with migration of the double bond; synonymous with 1, 4 addition; the most common examples include this type of addition to 1, 3-dienes & to alpha, Beta-unsaturated carbonyl compounds

19
Q

Kinetic control

A

reaction in which the major product is the one that is formed at the fastest rate

20
Q

Thermodynamic control

A

reaction in which the reaction conditions permit 2 or more products to equilibrate, giving predominance of the most stable product

21
Q

Diels-Alder reaction

A

conjugate addition of an alkene to a diene

22
Q

Dienophile

A

“diene seeker”; the alkene that adds to the diene

23
Q

Cycloaddition

A

addition in which a ring is formed via a cyclic transition state

24
Q

Pericyclic reactions

A

concerted reactions such as Diels-Alder cycloaddition that proceed through a cyclic transition state

25
Q

Alder rule

A

rule of maximum accumulation of unsaturation: in a Diels-Alder raction, the major stereoisomer is derived from the transition state in which unsaturated groups in the dienophile are endo with respect to the diene

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