Catalytic asymmetric aldol-type reactions using a chiral (acyloxy)borane complex
Catalytic asymmetric aldol-type reactions using a chiral (acyloxy)borane complex
复制标题
使用手性（酰氧基）硼烷络合物催化不对称羟醛型反应
DOI：
10.1246/bcsj.66.3483
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发表时间：
1993
影响因子：
4
通讯作者：
Hisashi Yamamoto
中科院分区：
文献类型：
--
作者：
K. Ishihara;Tohru Maruyama;Makoto Mouri;Qing Gao;K. Furuta*;Hisashi Yamamoto
在BH3·THF合成的手性(酰氧基)硼烷(CAB)络合物(CAB)和手性单O-酰化酒石酸的存在下，去手性硅烯醇醚或酮硅缩醛与去手性醛反应生成相应的羟醛类加合物，产率较高，对映和非对映选择性较高。此外，由3，5-二(三氟甲基)苯基硼酸和手性酒石酸衍生物制备的CAB络合物的用量为10-20摩尔%，可以在不降低对映体选择性的情况下提高羟醛类反应的反应活性。由邻苯氧基苯基硼酸和手性酒石酸衍生物制备的CAB络合物的摩尔分数为20mo%，在不降低化学产率的情况下，也可以提高对映体选择性。所观察到的亲核剂对醛的羰基碳的赤道选择性和表面攻击表明扩展的过渡态模型是适用的。
In the presence of 20 mol% of a chiral (acyloxy)borane (CAB) complex prepared from BH3·THF and a chiral mono-O-acylated tartaric acid, achiral silyl enol ethers or ketene silyl acetals react with achiral aldehydes to afford the corresponding aldol-type adducts in good yields with high enantio- and diastereoselectivities. Furthermore, the reactivity of aldol-type reactions can be improved without reducing the enantioselectivity by use of 10—20 mol% of the CAB complex prepared from 3,5-bis(trifluoromethyl)phenylboronic acid and chiral tartaric acid derivative. The enantioselectivity can also be improved without reducing the chemical yield by use of 20 mol% of the CAB complex prepared from o-phenoxyphenylboronic acid and chiral tartaric acid derivative. The observed erythro selectivities and re-face attack of nucleophiles on carbonyl carbon of aldehydes imply that the extended transition state model is applicable.