Term
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Definition
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Term
| retrosynthetic analysis/ antithesis |
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Definition
| the construction of a synthetic tree by working backward from the target molecule |
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Term
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Definition
| disconnections, cleavage of C-C bonds, functional group interconversions |
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Term
| Synthons are fragments resulting from... |
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Definition
| disconnection of C-C bonds of the target molecule |
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Term
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Definition
| actual substrates used for forward synthesis |
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Term
| E class (electrophilic, C+) (6) |
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Definition
| -NH2, -OH, -OR, =O, -NR, -X |
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Term
| G class (nucleophilic, C-) (4) |
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Definition
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Term
| A class (can be + or -) (8) |
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Definition
| -BR2, C=CR2, C≡CR, -NO2, R≡N, -SR, S(O)R, -SO2R |
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Term
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Definition
| positive charges placed at carbon atoms bonded to E class groups |
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Term
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Definition
| one E class group bonded to a carbon with a + charge, where as other E group resides on carbon with - charge |
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Term
| Why is it smarter to use enamine to use enolate in certain conditions? |
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Definition
| Enolate is strong enough base to cause Darzen's Condensation |
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Term
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Definition
| reversal of positive polarity of the carbonyl group so it acts as a formal or acyl anion would be synthetically very attractive |
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Term
| The a-hydrogens of nitroalkanes are appreciably acidic due to |
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Definition
| resonance stabilization of the anion |
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Term
| O-protected cyanohydrins contain |
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Definition
| a masked carbonyl group with inverted polarity. |
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Term
| The alpha-carbon of an O-protected cyanohydrin is sufficently activated by the _____ moiety |
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Definition
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Term
| Formation of new carbon-carbon bonds are of paramount importance in organic chemistry because |
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Definition
| they allow the construction of complex structures from smaller starting materials. |
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Term
| Choose disconnections in which functional groups are close to the C-C bonds to be formed since |
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Definition
| the presence of functional groups often facilitates bond making by a substitution reaction. |
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Term
| Is it advantageous to cutting a molecule at a branching point? |
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Definition
| this may lead to linear fragments that are generally more readily accessible, either by synthesis or from a commercial source |
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Term
| Symmetry in the TM simplifies |
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Definition
| s the overall synthesis by decreasing the number of steps required for obtaining the TM |
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Term
| Introduction of an activating (auxiliary) functional group may facilitate |
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Definition
| carbon-carbon bond formation |
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Term
| Disconnection of an internal (E)- or (Z)-double bond or a side chain of an alkene suggests |
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Definition
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Term
| The presence of a six-member ring, especially a cyclohexene derivative, suggests |
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Definition
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Term
| The structural feature of an a, P-unsaturated ketone or a P-hydroxy ketone in a six-member ring suggests |
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Definition
| double disconnection coupled with functional group interconversions [Michael addition followed by intramolecular aldol condensation |
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Term
Selected Functional groups interconversions:
Alkyl chlorides
RCl --> ROH (4) |
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Definition
SOCl2 +ZnCl2
PCl3 or PCl5
Ph3P + Cl2 --> [Ph3P(+)-Cl]Cl-
Ph3P +CCl4 --> [Ph3P(+)-CCl3]Cl- |
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Term
Selected Functional groups interconversions Alkyl bromides:
R-Br --> ROH
(3) |
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Definition
Ph3P + Br2 --> [Ph3P(+)-Br]Br-
Ph3P +CBr4 --> [Ph3P(+)-CBr3]Br-
PBr3 |
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Term
Selected Functional groups interconversions Alkyl bromides:
R-Br--> RCOOH |
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Definition
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Term
Selected Functional groups interconversions Alkyl bromides:
RCH2CH2-Br --> RCH=CH2 (2) |
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Definition
HBr + free-radical initiator
a.) BH3*THF; b.) Br2 + NaOCH3 |
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Term
Selected Functional groups interconversions:
Allylic and propargylic bromides
Allylic bromination-->alkene |
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Definition
| NBS + free-radical initiator |
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Term
Selected Functional groups interconversions:
Allylic and propargylic bromides
RCH=CH2Br --> RCH=CHCH2OH (2) |
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Definition
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Term
Selected Functional groups interconversions:
Allylic and propargylic bromides
RC≡CCH2Br-->RC≡CH2OH |
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Definition
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Term
Selected Functional groups interconversions: alkyl iodides
R-I --> ROH |
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Definition
| (PhO)3P + CH3I --> [(PhO)3P(+)-CH3] |
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Term
Selected Functional groups interconversions: alkyl iodides
R-I-->R-Br |
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Definition
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Term
Selected Functional groups interconversions: alkyl iodides
R-I-->ROTs |
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Definition
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Term
Selected Functional groups interconversions: Nitriles
RCH2-CN --> RCH2-X |
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Definition
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Term
Selected Functional groups interconversions: Nitriles
RCH2-CN --> RCH2CONH2 |
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Definition
| oxalyl chloride + DMF +CH3CN |
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Term
Selected Functional groups interconversions:
Nitriles
R-CN --> RCONH2 (2) |
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Definition
| (CF3SO2)2O or (CHO)n + HCOOH |
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Term
Selected Functional groups interconversions: Nitriles
R-CN --> RCH=NOH |
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Definition
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Term
Selected Functional groups interconversions:
Nitriles
R-CN --> R2C=O |
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Definition
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Term
Selected functional groups interconversions: 1" and 2" Alcohols
RCH2CH2OH --> RCH2COOH (2) |
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Definition
a.) LiAlH4 b.) H3O+ OR
BH3, THF |
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Term
Selected functional groups interconversions: 1" and 2" Alcohols
RCH2CH2OH --> RCH2COOR |
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Definition
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Term
Selected functional groups interconversions: 1" and 2" Alcohols
RCH2CH2OH --> RCH2CHO |
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Definition
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Term
Selected functional groups interconversions: 1" and 2" Alcohols
RCH2CH2OH --> RCH=CH2 |
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Definition
| a.) BH3, THF b. NaOH, H2O2 |
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Term
Selected functional groups interconversions: 1" and 2" Alcohols
R2CH-OH --> R2C=O (2) |
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Definition
NaBH4, EtOH or
a.)LiAlH4 b.) H3O+ |
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Term
Selected functional groups interconversions: 1" and 2" Alcohols
R-CH-CH3 --> RCH=CH2 (2)
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OH |
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Definition
Hg(oAc)2, H2O
OR
NaBH4, NaOH |
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Term
| The choice of a method for synthesizing a compound derived from a retrosynthetic analysis should be based on the following criteria (11) |
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Definition
Regiochemistry
Chemoselectivity
Stereoselectivity
Efficiency
High yields
avaliability and cost of starting matterials
most environmentally friendly route
Simplicity
Isolation and purification of reaction products
Possibility of a convergent synthesis or "one-pot process" |
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Term
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Definition
| , the preferential addition of the reagent in only one of two possible regions or directions |
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Term
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Definition
| selective reaction of one functional group in the presence of other functional groups |
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Term
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Definition
| , the exclusive or predominant formation of one of several possible stereoisomeric products |
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Term
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Definition
| the hypothetical TM is assembled in a step- wise manner |
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Term
| seven-step LINEAR synthesis of the hypothetical TM below, if the yield of the intermediate at each step is 80%, the overall yield will be |
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Definition
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Term
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Definition
| should be considered in which two or more frag- ments of the TM are prepared separately and then joined at the latest-possible stage of the synthesis |
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Term
For convergent synthesis:
The overall yield in a convergent synthesis is the product of yields |
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Definition
| of the longest linear sequence |
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Term
| For convergent synthesis 80% yield of intermediate... or the synthesis of the above TM, only three stages are involved in the convergent strategy shown below, with an overall yield |
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Definition
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Term
| Another important consideration in choosing a convergent protocol |
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Definition
| is that failure of a single step in a multistep synthesis does not nullify the chosen synthetic approach as a whole, whereas failure of a single step in a linear scheme may require a revision of the whole plan. |
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Term
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Definition
| involve careful design of a multistep reaction in a one-pot sequence in which the first step creates the functionality to trigger the second reaction and so on, making this approach economical and environmentally friendly |
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