<MultiModal>![[H][C@]12[C@](C/C2=N\OC(C3=CC=CC=C3)=O)([H])C=CC1.C=C(C1=CC=CC=C1)C2=CC=CC=C2>$Cu(OTf)_2$  (10 mol%),$1,4-Dioxane/PhCF_3 (1:1)$>A](/media/uploads/1aac3da6-266a-4838-b22c-e2b06941def8.png)</MultiModal>

Please select the most suitable product A
<MultiModal>![[H][C@]12[C@](C/C2=N\OC(C3=CC=CC=C3)=O)([H])C=CC1.C=C(C1=CC=CC=C1)C2=CC=CC=C2>$Cu(OTf)_2$  (10 mol%),$1,4-Dioxane/PhCF_3 (1:1)$>A](/media/uploads/1aac3da6-266a-4838-b22c-e2b06941def8.png)</MultiModal>

请选出最合适的产物A
<MultiModal>![[H][C@]1(CC#N)C=CC[C@@H]1/C=C(C2=CC=CC=C2)/C3=CC=CC=C3](/media/uploads/b105d191-51ed-401c-90bb-da8036cde5b6.png)</MultiModal>
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<MultiModal>![[H][C@@]1(CC#N)C=CC[C@H]1/C=C(C2=CC=CC=C2)/C3=CC=CC=C3](/media/uploads/6a434e38-4d75-4ffd-98b7-e5b71dee7344.png)</MultiModal>
This reaction is a radical reaction  

<Checkpoint>[This reaction is a radical reaction](1)</Checkpoint>  

The $Cu$ in the reaction system acts as a catalyst  

<Checkpoint>[The $Cu$ in the reaction system acts as a catalyst](1)</Checkpoint>  

$Cu(I)$ first donates a single electron, causing the cleavage of the weaker N-O bond and forming a radical intermediate <MultiModal>![[H][C@]12[C@](CC2=[N])([H])C=CC1](/media/uploads/b4f84bba-9a65-4fed-983c-b3de875573e4.png)</MultiModal>  

<Checkpoint>[$Cu(I)$ first donates a single electron, causing the cleavage of the weaker N-O bond and forming a radical intermediate](1)</Checkpoint>  

Subsequently, this unstable intermediate rapidly undergoes ring-opening to form a more stable carbon radical <MultiModal>![[H][C@]1(CC#N)C=CC[C]1[H]](/media/uploads/153b2c42-f7ce-4ed7-a531-408de1540298.png)</MultiModal>  

<Checkpoint>[Subsequently, this unstable intermediate rapidly undergoes ring-opening to form a more stable carbon radical](1)</Checkpoint>  

Next, $Cu(II)$ oxidizes this radical to form a carbocation <MultiModal>![[H][C@]1(CC#N)C=CC[CH+]1](/media/uploads/689af528-cd2c-4a6b-9dcf-0d7c16d7ee95.png)</MultiModal>  

<Checkpoint>[Next, $Cu(II)$ oxidizes this radical to form a carbocation](1)</Checkpoint>  

Due to the greater steric hindrance above this carbocation compared to below, it is selectively captured from below by 1,1-diphenylethylene <MultiModal>![[H][C@]1(CC#N)C=CC[C@@H]1C[C+](C2=CC=CC=C2)C3=CC=CC=C3](/media/uploads/bcf98b7f-f37a-4fdb-a644-b89c98b521d1.png)</MultiModal>  

<Checkpoint>[Due to the greater steric hindrance above this carbocation compared to below, it is selectively captured from below by 1,1-diphenylethylene](1)</Checkpoint>  

Finally, a proton is eliminated to form product A
该反应为自由基反应

<Checkpoint>[该反应为自由基反应](1)</Checkpoint>

反应体系中的$Cu$为催化剂

<Checkpoint>[反应体系中的$Cu$为催化剂](1)</Checkpoint>

$Cu(I)$首先给出一个单电子，使得较弱的N-O键发生裂解，形成自由基中间体<MultiModal>![[H][C@]12[C@](CC2=[N])([H])C=CC1](/media/uploads/b4f84bba-9a65-4fed-983c-b3de875573e4.png)</MultiModal>

<Checkpoint>[$Cu(I)$首先给出一个单电子，使得较弱的N-O键发生裂解，形成自由基中间体](1)</Checkpoint>

随后该不稳定中间体迅速发生开环，形成较稳定的碳自由基<MultiModal>![[H][C@]1(CC#N)C=CC[C]1[H]](/media/uploads/153b2c42-f7ce-4ed7-a531-408de1540298.png)</MultiModal>

<Checkpoint>[随后该不稳定中间体迅速发生开环，形成较稳定的碳自由基](1)</Checkpoint>

接着$Cu(II)$将该自由基氧化，形成碳正离子<MultiModal>![[H][C@]1(CC#N)C=CC[CH+]1](/media/uploads/689af528-cd2c-4a6b-9dcf-0d7c16d7ee95.png)</MultiModal>

<Checkpoint>[接着$Cu(II)$将该自由基氧化，形成碳正离子](1)</Checkpoint>

由于该碳正离子上方的位阻大于下方，因此被1,1-二苯乙烯选择性地从下方捕获<MultiModal>![[H][C@]1(CC#N)C=CC[C@@H]1C[C+](C2=CC=CC=C2)C3=CC=CC=C3](/media/uploads/bcf98b7f-f37a-4fdb-a644-b89c98b521d1.png)</MultiModal>

<Checkpoint>[由于该碳正离子上方的位阻大于下方，因此被1,1-二苯乙烯选择性地从下方捕获](1)</Checkpoint>

最后脱去质子形成产物A