Stereochemistry - Organic Chemistry - Chemistry Previous Year Questions

1

2008 · Chemistry · Organic Chemistry · Stereochemistry

Chemistry (CY) 2008

The number of optically active stereoisomers possible for 1,3-cyclohexanediol in its chair conformation is

A

4

B

3

C

2

D

1

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2

2008 · Chemistry · Organic Chemistry · Stereochemistry

Chemistry (CY) 2008

In the following reaction,
D-Glyceraldehyde + HCN → X + Y (2 diastereomers)
The absolute configurations of the chiral centres in X and Y are

A

2S, 3R and 2R, 3R

B

2R, 3R and 2R, 3S

C

2S, 3S and 2R, 3R

D

2S, 3R and 2S, 3R

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3

2009 · Chemistry · Organic Chemistry · Stereochemistry

Chemistry (CY) 2009

For the compound [image] the stereochemical notations are

A

2Z, 4R

B

2Z, 4S

C

2E, 4R

D

2E, 4S

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4

2013 · Chemistry · Organic Chemistry · Stereochemistry

Chemistry (CY) 2013

The maximum number of stereoisomers possible for the compound given below is ______.

A

B

C

D

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5

2016 · Chemistry · Organic Chemistry · Stereochemistry

Chemistry (CY) 2016

Ring flipping of the compound in the following conformation leads to

A

B

C

D

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6

2016 · Chemistry · Organic Chemistry · Stereochemistry

Chemistry (CY) 2016

The compound in 'R' configuration is

A

B

C

D

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7

2016 · Chemistry · Organic Chemistry · Stereochemistry

Chemistry (CY) 2016

The favourable transition state leading to the formation of the product in the following reaction, is
Reaction: Ph-CO-CH(B(Chx)2)-CH3 (i) PhCHO, -78 °C (ii) H2O2, NaOH → Ph-CO-CH(OH)-CH(Ph)-CH3, Chx = cyclohexyl

A

Structure A

B

Structure B

C

Structure C

D

Structure D

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8

2019 · Chemistry · Organic Chemistry · Stereochemistry

Chemistry (CY) 2019

In the following reaction, the stereochemistry of the major product is predicted by the

A

Cram's model

B

Cram's chelation model

C

Felkin model

D

Felkin-Anh model

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9

2019 · Chemistry · Organic Chemistry · Stereochemistry

Chemistry (CY) 2019

Among the following compounds, the number of compounds that DO NOT exhibit optical activity at room temperature is __________.

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10

2019 · Chemistry · Organic Chemistry · Stereochemistry

Chemistry (CY) 2019

The specific rotation of optically pure (R)-2-bromobutane is −112.00. A given sample of 2-bromobutane exhibited a specific rotation of −82.88. The percentage of (S)-(+)-enantiomer present in this sample is ______.

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11

2023 · Chemistry · Organic Chemistry · Stereochemistry

Chemistry (CY) 2023

The topicity relationship of H_a and H_b in X, Y and Z are, respectively,

A

Diastereotopic, Homotopic and Enantiotopic

B

Homotopic, Enantiotopic and Enantiotopic

C

Homotopic, Homotopic and Enantiotopic

D

Diastereotopic, Enantiotopic and Homotopic

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12

2023 · Chemistry · Organic Chemistry · Stereochemistry

Chemistry (CY) 2023

The stereoisomer(s) of G giving the depicted product is(are)

A

Chemical structure with a stereocenter, with H and SiMe3 up, and C6H9 and OH down, C5H11 down.

B

Chemical structure with a stereocenter, with H and SiMe3 up, and C6H9 down, OH down, Me up.

C

Chemical structure with a stereocenter, with Me3Si up, H up, C6H9 down, HO down, Me up.

D

Chemical structure with a stereocenter, with Me3Si up, H down, C6H9 down, Me up, OH down.

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13

2024 · Chemistry · Organic Chemistry · Stereochemistry

Chemistry (CY) 2024

Among the following, the chiral compound is

A

P

B

Q

C

R

D

S

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14

2024 · Chemistry · Organic Chemistry · Stereochemistry

Chemistry (CY) 2024

The correct statement(s) for decalin is (are)

A

cis-Decalin is thermodynamically less stable than trans-decalin.

B

cis-Decalin contains plane of symmetry.

C

trans-Decalin undergoes ring inversion.

D

trans-Decalin belongs to the point group of C_2h.

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15

2024 · Chemistry · Organic Chemistry · Stereochemistry

Chemistry (CY) 2024

The correct statement(s) about the relationship for the H-atoms in the following compounds is (are):

A

H₁ and H₃ are enantiotopic; H₂ and H₅ are diastereotopic.

B

H₁ and H₃ are diastereotopic; H₂ and H₃ are enantiotopic.

C

H₅ and H₇ are enantiotopic; H₆ and H₇ are homotopic.

D

H₅ and H₇ are homotopic; H₆ and H₇ are enantiotopic.

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16

2025 · Chemistry · Organic Chemistry · Stereochemistry

Chemistry (CY) 2025

The specific rotation of enantiomerically pure (S)-2-butanol is +14°. The specific rotation of enantiomeric mixture of 2-butanol obtained from an asymmetric reduction of 2-butanone is found to be +7°. The percentage of (R)-2-butanol present in the reaction mixture is ____ (in integer).

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17

2025 · Chemistry · Organic Chemistry · Stereochemistry

Chemistry (CY) 2025

In the following asymmetric transformation, the key aldol reaction involves the attack of

(A) Si face of enolate on to the Re face of aldehyde
(B) Si face of enolate on to the Si face of aldehyde
(C) Re face of enolate on to the Re face of aldehyde
(D) Re face of enolate on to the Si face of aldehyde

A

Si face of enolate on to the Re face of aldehyde

B

Si face of enolate on to the Si face of aldehyde

C

Re face of enolate on to the Re face of aldehyde

D

Re face of enolate on to the Si face of aldehyde

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18

2025 · Chemistry · Organic Chemistry · Stereochemistry

Chemistry (CY) 2025

For the following reaction, the possible product(s) is/are

A

B

C

D

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19

2007 · Chemistry · Organic Chemistry · Stereochemistry

Chemistry (CY) 2007

The result of the reduction of either (R) or (S) 2-methylcyclohexanone, in separate reactions, using LiAlH₄ is that the reduction of

A

the R enantiomer is stereoselective

B

the R enantiomer is stereospecific

C

the S enantiomer is stereospecific

D

both the R and S enantiomers is stereoselective

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20

2007 · Chemistry · Organic Chemistry · Stereochemistry

Chemistry (CY) 2007

The molecule(s) that exist as meso structure(s) is / are

A

only M

B

both K and L

C

only L

D

only K

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