The radical cyclization process sometimes exhibits certain stereoselectivity:

<MultiModal>![C=CCC(C)C[C]([H])[H]](/media/uploads/1d011714-960c-4ffd-9413-d1666cff25f2.png)</MultiModal>

<MultiModal>![C=CCCC(C)[C]([H])[H]](/media/uploads/00c9b5ab-e25b-48ec-bb2f-f1cd5104d3bf.png)</MultiModal>

Given that the system contains $\mathrm{Bu_3SnH}$, please predict the product structures of the above two reactions respectively and determine whether they have enantiomers.
自由基关环过程有时具有一定的立体选择性：

<MultiModal>![C=CCC(C)C[C]([H])[H]](/media/uploads/1d011714-960c-4ffd-9413-d1666cff25f2.png)</MultiModal>

<MultiModal>![C=CCCC(C)[C]([H])[H]](/media/uploads/00c9b5ab-e25b-48ec-bb2f-f1cd5104d3bf.png)</MultiModal>

已知体系中含有$\mathrm{Bu_3SnH}$,请分别预测以上两个反应的产物结构,并判断其是否有对映异构体。
<MultiModal>![C[C@@H]1C[C@H](C)CC1](/media/uploads/b96c40b3-2a34-4dd6-b243-e959ccd3a3a1.png)</MultiModal>

No enantiomers

<MultiModal>![C[C@H]1C[C@H](C)CC1](/media/uploads/c5f27f21-c404-453d-a0d4-f7ddbd45cb96.png)</MultiModal>

Has enantiomers
<MultiModal>![C[C@@H]1C[C@H](C)CC1](/media/uploads/b96c40b3-2a34-4dd6-b243-e959ccd3a3a1.png)</MultiModal>

No enantiomers

<MultiModal>![C[C@@H]1C[C@H](C)CC1](/media/uploads/b96c40b3-2a34-4dd6-b243-e959ccd3a3a1.png)</MultiModal>

No enantiomers
<MultiModal>![C[C@H]1C[C@H](C)CC1](/media/uploads/c5f27f21-c404-453d-a0d4-f7ddbd45cb96.png)</MultiModal>

No enantiomers

<MultiModal>![C[C@@H]1C[C@H](C)CC1](/media/uploads/b96c40b3-2a34-4dd6-b243-e959ccd3a3a1.png)</MultiModal>

No enantiomers
<MultiModal>![C[C@H]1C[C@H](C)CC1](/media/uploads/c5f27f21-c404-453d-a0d4-f7ddbd45cb96.png)</MultiModal>

Has enantiomers

<MultiModal>![C[C@@H]1C[C@H](C)CC1](/media/uploads/b96c40b3-2a34-4dd6-b243-e959ccd3a3a1.png)</MultiModal>

No enantiomers
<MultiModal>![C[C@H]1C[C@H](C)CC1](/media/uploads/c5f27f21-c404-453d-a0d4-f7ddbd45cb96.png)</MultiModal>  

No enantiomers  

<MultiModal>![C[C@H]1C[C@H](C)CC1](/media/uploads/c5f27f21-c404-453d-a0d4-f7ddbd45cb96.png)</MultiModal>  

No enantiomers
<MultiModal>![C[C@H]1C[C@H](C)CC1](/media/uploads/c5f27f21-c404-453d-a0d4-f7ddbd45cb96.png)</MultiModal>  

Has enantiomers  

<MultiModal>![C[C@H]1C[C@H](C)CC1](/media/uploads/c5f27f21-c404-453d-a0d4-f7ddbd45cb96.png)</MultiModal>  

Has enantiomers
<MultiModal>![CC1CCCCC1](/media/uploads/d694df7d-1815-4008-91ce-4473bb07703c.png)</MultiModal>

No enantiomers  

<MultiModal>![C[C@H]1C[C@H](C)CC1](/media/uploads/c5f27f21-c404-453d-a0d4-f7ddbd45cb96.png)</MultiModal>  

No enantiomers
<MultiModal>![CC1CCCCC1](/media/uploads/d694df7d-1815-4008-91ce-4473bb07703c.png)</MultiModal>

No enantiomers  

<MultiModal>![C[C@H]1C[C@H](C)CC1](/media/uploads/c5f27f21-c404-453d-a0d4-f7ddbd45cb96.png)</MultiModal>  

Has enantiomers
<MultiModal>![CC1CCCCC1](/media/uploads/d694df7d-1815-4008-91ce-4473bb07703c.png)</MultiModal>  

No enantiomers  

<MultiModal>![C[C@@H]1C[C@H](C)CC1](/media/uploads/b96c40b3-2a34-4dd6-b243-e959ccd3a3a1.png)</MultiModal>  

No enantiomers
<MultiModal>![C[C@H]1C[C@H](C)CC1](/media/uploads/c5f27f21-c404-453d-a0d4-f7ddbd45cb96.png)</MultiModal>

Has enantiomers

<MultiModal>![CC1CCCCC1](/media/uploads/d694df7d-1815-4008-91ce-4473bb07703c.png)</MultiModal>

No enantiomers
<MultiModal>![C[C@H]1C[C@H](C)CC1](/media/uploads/c5f27f21-c404-453d-a0d4-f7ddbd45cb96.png)</MultiModal>

No enantiomers

<MultiModal>![CC1CCCCC1](/media/uploads/d694df7d-1815-4008-91ce-4473bb07703c.png)</MultiModal>

No enantiomers
<MultiModal>![C[C@@H]1C[C@H](C)CC1](/media/uploads/b96c40b3-2a34-4dd6-b243-e959ccd3a3a1.png)</MultiModal>

No enantiomers  

<MultiModal>![CC1CCCCC1](/media/uploads/d694df7d-1815-4008-91ce-4473bb07703c.png)</MultiModal>  

No enantiomers
<MultiModal>![CC1CCCCC1](/media/uploads/d694df7d-1815-4008-91ce-4473bb07703c.png)</MultiModal>

No enantiomers

<MultiModal>![CC1CCCCC1](/media/uploads/d694df7d-1815-4008-91ce-4473bb07703c.png)</MultiModal>

No enantiomers
<MultiModal>![C[C@@H]1C[C@H](C)CC1](/media/uploads/b96c40b3-2a34-4dd6-b243-e959ccd3a3a1.png)</MultiModal>

No enantiomer

<MultiModal>![C[C@H]1C[C@H](C)CC1](/media/uploads/c5f27f21-c404-453d-a0d4-f7ddbd45cb96.png)</MultiModal>

No enantiomer
<MultiModal>![C[C@@H]1C[C@H](C)CC1](/media/uploads/b96c40b3-2a34-4dd6-b243-e959ccd3a3a1.png)</MultiModal>

没有对映异构体

<MultiModal>![C[C@H]1C[C@H](C)CC1](/media/uploads/c5f27f21-c404-453d-a0d4-f7ddbd45cb96.png)</MultiModal>

有对映异构体
<MultiModal>![C[C@@H]1C[C@H](C)CC1](/media/uploads/b96c40b3-2a34-4dd6-b243-e959ccd3a3a1.png)</MultiModal>

没有对映异构体

<MultiModal>![C[C@@H]1C[C@H](C)CC1](/media/uploads/b96c40b3-2a34-4dd6-b243-e959ccd3a3a1.png)</MultiModal>

没有对映异构体
<MultiModal>![C[C@H]1C[C@H](C)CC1](/media/uploads/c5f27f21-c404-453d-a0d4-f7ddbd45cb96.png)</MultiModal>

没有对映异构体

<MultiModal>![C[C@@H]1C[C@H](C)CC1](/media/uploads/b96c40b3-2a34-4dd6-b243-e959ccd3a3a1.png)</MultiModal>

没有对映异构体
<MultiModal>![C[C@H]1C[C@H](C)CC1](/media/uploads/c5f27f21-c404-453d-a0d4-f7ddbd45cb96.png)</MultiModal>

有对映异构体

<MultiModal>![C[C@@H]1C[C@H](C)CC1](/media/uploads/b96c40b3-2a34-4dd6-b243-e959ccd3a3a1.png)</MultiModal>

没有对映异构体
<MultiModal>![C[C@H]1C[C@H](C)CC1](/media/uploads/c5f27f21-c404-453d-a0d4-f7ddbd45cb96.png)</MultiModal>

没有对映异构体

<MultiModal>![C[C@H]1C[C@H](C)CC1](/media/uploads/c5f27f21-c404-453d-a0d4-f7ddbd45cb96.png)</MultiModal>

没有对映异构体
<MultiModal>![C[C@H]1C[C@H](C)CC1](/media/uploads/c5f27f21-c404-453d-a0d4-f7ddbd45cb96.png)</MultiModal>

有对映异构体

<MultiModal>![C[C@H]1C[C@H](C)CC1](/media/uploads/c5f27f21-c404-453d-a0d4-f7ddbd45cb96.png)</MultiModal>

有对映异构体
<MultiModal>![CC1CCCCC1](/media/uploads/d694df7d-1815-4008-91ce-4473bb07703c.png)</MultiModal>

没有对映异构体

<MultiModal>![C[C@H]1C[C@H](C)CC1](/media/uploads/c5f27f21-c404-453d-a0d4-f7ddbd45cb96.png)</MultiModal>

没有对映异构体
<MultiModal>![CC1CCCCC1](/media/uploads/d694df7d-1815-4008-91ce-4473bb07703c.png)</MultiModal>

没有对映异构体

<MultiModal>![C[C@H]1C[C@H](C)CC1](/media/uploads/c5f27f21-c404-453d-a0d4-f7ddbd45cb96.png)</MultiModal>

有对映异构体

<MultiModal>![CC1CCCCC1](/media/uploads/d694df7d-1815-4008-91ce-4473bb07703c.png)</MultiModal>

没有对映异构体

<MultiModal>![C[C@@H]1C[C@H](C)CC1](/media/uploads/b96c40b3-2a34-4dd6-b243-e959ccd3a3a1.png)</MultiModal>

没有对映异构体
<MultiModal>![C[C@H]1C[C@H](C)CC1](/media/uploads/c5f27f21-c404-453d-a0d4-f7ddbd45cb96.png)</MultiModal>

有对映异构体

<MultiModal>![CC1CCCCC1](/media/uploads/d694df7d-1815-4008-91ce-4473bb07703c.png)</MultiModal>

没有对映异构体
<MultiModal>![C[C@H]1C[C@H](C)CC1](/media/uploads/c5f27f21-c404-453d-a0d4-f7ddbd45cb96.png)</MultiModal>

没有对映异构体

<MultiModal>![CC1CCCCC1](/media/uploads/d694df7d-1815-4008-91ce-4473bb07703c.png)</MultiModal>

没有对映异构体
<MultiModal>![C[C@@H]1C[C@H](C)CC1](/media/uploads/b96c40b3-2a34-4dd6-b243-e959ccd3a3a1.png)</MultiModal>

没有对映异构体

<MultiModal>![CC1CCCCC1](/media/uploads/d694df7d-1815-4008-91ce-4473bb07703c.png)</MultiModal>

没有对映异构体
<MultiModal>![CC1CCCCC1](/media/uploads/d694df7d-1815-4008-91ce-4473bb07703c.png)</MultiModal>

没有对映异构体

<MultiModal>![CC1CCCCC1](/media/uploads/d694df7d-1815-4008-91ce-4473bb07703c.png)</MultiModal>

没有对映异构体
<MultiModal>![C[C@@H]1C[C@H](C)CC1](/media/uploads/b96c40b3-2a34-4dd6-b243-e959ccd3a3a1.png)</MultiModal>

没有对映异构体

<MultiModal>![C[C@H]1C[C@H](C)CC1](/media/uploads/c5f27f21-c404-453d-a0d4-f7ddbd45cb96.png)</MultiModal>

没有对映异构体
The cyclization of alkyl radicals is less reversible and tends to yield the kinetically favored five-membered ring product.

<Checkpoint>[The cyclization of alkyl radicals is less reversible and tends to yield the kinetically favored five-membered ring product](2)</Checkpoint>

For the cyclization of the first substrate, the transition state energy is lower when the methyl group is in the equatorial position.

<MultiModal>![cc1C[C@H](C)CC1](/media/uploads/6cd08e8b-241b-4924-8de5-65d90a7ab9fe.png)</MultiModal>

<Checkpoint>[For the cyclization of the first substrate, the transition state energy is lower when the methyl group is in the equatorial position](1)</Checkpoint>

Therefore, the first reaction yields the cis product.

<MultiModal>![C[C@@H]1C[C@H](C)CC1](/media/uploads/b96c40b3-2a34-4dd6-b243-e959ccd3a3a1.png)</MultiModal>

This product contains a mirror plane and thus does not exhibit enantiomerism.

<Checkpoint>[This product contains a mirror plane and thus does not exhibit enantiomerism](1)</Checkpoint>

For the cyclization of the second substrate, the transition state energy is also lower when the methyl group is in the equatorial position.

<MultiModal>![cc1CC[C@@H](C)C1](/media/uploads/46010f8e-0fda-46de-bee4-ad34e1ffa4a9.png)</MultiModal>

<Checkpoint>[For the cyclization of the second substrate, the transition state energy is also lower when the methyl group is in the equatorial position](1)</Checkpoint>

Therefore, the second reaction yields the trans product.

<MultiModal>![C[C@H]1C[C@H](C)CC1](/media/uploads/c5f27f21-c404-453d-a0d4-f7ddbd45cb96.png)</MultiModal>

This product lacks a mirror plane, inversion center, or improper rotation axis and is thus optically active.

<Checkpoint>[This product lacks a mirror plane, inversion center, or improper rotation axis and is thus optically active](1)</Checkpoint>

In summary, the correct answer to this question is A.
烷基自由基关环可逆性较差,容易得到动力学有利的五元环产物

<Checkpoint>[烷基自由基关环可逆性较差,容易得到动力学有利的五元环产物](2)</Checkpoint>

对于第一个底物的成环反应,甲基处于平伏键位置时过渡态能量较低

<MultiModal>![cc1C[C@H](C)CC1](/media/uploads/6cd08e8b-241b-4924-8de5-65d90a7ab9fe.png)</MultiModal>

<Checkpoint>[对于第一个底物的成环反应,甲基处于平伏键位置时过渡态能量较低](1)</Checkpoint>

因此第一个反应得到顺式产物

<MultiModal>![C[C@@H]1C[C@H](C)CC1](/media/uploads/b96c40b3-2a34-4dd6-b243-e959ccd3a3a1.png)</MultiModal>

此产物中存在镜面，因此不具有对映异构体。

<Checkpoint>[此产物中存在镜面，因此不具有对映异构体](1)</Checkpoint>

对于第二个底物的成环反应,同样甲基处于平伏键位置时过渡态能量较低

<MultiModal>![cc1CC[C@@H](C)C1](/media/uploads/46010f8e-0fda-46de-bee4-ad34e1ffa4a9.png)</MultiModal>

<Checkpoint>[对于第二个底物的成环反应,同样甲基处于平伏键位置时过渡态能量较低](1)</Checkpoint>

因此第二个反应得到反式产物

<MultiModal>![C[C@H]1C[C@H](C)CC1](/media/uploads/c5f27f21-c404-453d-a0d4-f7ddbd45cb96.png)</MultiModal>

此产物中不存在镜面、对称中心或映轴，因此具有光学活性。

<Checkpoint>[此产物中不存在镜面、对称中心或映轴，因此具有光学活性](1)</Checkpoint>

综上所述，本题答案为A.