Predict for which substrates the first-order kinetic isotope effect (KIE) can be observed when singlet oxygen $^1\mathrm{O}_{2}$ reacts with them. Consider only the reaction with a single molecule.

<MultiModal>![C/C(C)=C(C([2H])([2H])[2H])\C([2H])([2H])[2H],Substrate 1](/media/uploads/65e355bf-7016-4ab0-a419-505fd5ca1724.png)</MultiModal>

Substrate 1

<MultiModal>![C/C(C([2H])([2H])[2H])=C(C)\C([2H])([2H])[2H],Substrate 2](/media/uploads/ea238acc-8e16-4651-a819-c1da6aeec3fb.png)</MultiModal>

Substrate 2

<MultiModal>![C/C(C([2H])([2H])[2H])=C(C)/C([2H])([2H])[2H],Substrate 3](/media/uploads/63a5ae85-a4d4-4d15-9e5f-1a4103a60015.png)</MultiModal>

Substrate 3
请预测单线态氧$^1\mathrm{O}_{2}$与以下哪些底物发生反应时，能观测到一级动力学同位素效应(KIE)？仅考虑与单个分子反应的情况。

<MultiModal>![C/C(C)=C(C([2H])([2H])[2H])\C([2H])([2H])[2H],底物1](/media/uploads/65e355bf-7016-4ab0-a419-505fd5ca1724.png)</MultiModal>

底物1

<MultiModal>![C/C(C([2H])([2H])[2H])=C(C)\C([2H])([2H])[2H],底物2](/media/uploads/ea238acc-8e16-4651-a819-c1da6aeec3fb.png)</MultiModal>

底物2

<MultiModal>![C/C(C([2H])([2H])[2H])=C(C)/C([2H])([2H])[2H],底物3](/media/uploads/63a5ae85-a4d4-4d15-9e5f-1a4103a60015.png)</MultiModal>

底物3
All other options are incorrect
Only option 1
Only option 2
Only option 3
Only options 1, 2
Only options 1, 3
Only options 2, 3
Option 1, 2, 3
其他选项均不正确
只有选项1
只有选项2
只有选项3
只有选项1、2
只有选项1、3
只有选项2、3
选项1、2、3
The kinetic isotope effect arises from the difference in zero-point energy between C-H and C-D bonds.

<Checkpoint>[The kinetic isotope effect arises from the difference in zero-point energy between C-H and C-D bonds](1)</Checkpoint>

This is the transition state of the reaction

<MultiModal>![[H]CC(C[H])([O+]1[O-])C1(C[H])C[H]](/media/uploads/5a7cc1eb-ea7e-446d-bfb5-e15ce429b5be.png)</MultiModal>

For substrate 3, regardless of which side the peroxide faces in the intermediate, only one of H or D can be attacked, thus no KIE is generated.

<Checkpoint>[For substrate 3, regardless of which side the peroxide faces in the intermediate, only one of H or D can be attacked, thus no KIE is generated](1)</Checkpoint>

Whereas for substrates 1 and 2, regardless of which side the peroxide faces in the intermediate, there is competition between attacking H and D, hence KIE exists.

<Checkpoint>[Whereas for substrates 1 and 2, regardless of which side the peroxide faces in the intermediate, there is competition between attacking H and D, hence KIE exists](1)</Checkpoint>
动力学同位素效应是由于 C-H 键和 C-D 键之间的零点能有差别造成的

<Checkpoint>[动力学同位素效应是由于 C-H 键和 C-D 键之间的零点能有差别造成的](1)</Checkpoint>

这是反应的过渡态

<MultiModal>![[H]CC(C[H])([O+]1[O-])C1(C[H])C[H]](/media/uploads/5a7cc1eb-ea7e-446d-bfb5-e15ce429b5be.png)</MultiModal>

速控步是烯丙基C-H/C-D键的断裂

<Checkpoint>[速控步是烯丙基C-H/C-D键的断裂](1)</Checkpoint>

对于底物1和2，单线态氧无论从双键的哪一侧进攻，其可以夺取的烯丙位上都同时存在甲基（$-CH_3$）和氘代甲基（$-CD_3$），因此C-H键断裂和C-D键断裂形成竞争关系，从而能观测到分子间KIE

<Checkpoint>[对于底物1和2，单线态氧无论从双键的哪一侧进攻，其可以夺取的烯丙位上都同时存在甲基（$-CH_3$）和氘代甲基（$-CD_3$），因此C-H键断裂和C-D键断裂形成竞争关系，从而能观测到分子间KIE](1)</Checkpoint>

对于底物3，无论中间体中过氧朝向哪一侧,均只可能进攻H或D中的一种,故不会产生KIE

<Checkpoint>[对于底物3，无论中间体中过氧朝向哪一侧,均只可能进攻H或D中的一种,故不会产生KIE](1)</Checkpoint>