标题:Chelation-Assisted Substrate-Controlled Asymmetric Lithiation-Allylboration of Chiral Carbamate 1,2,4-Butanetriol Acetonide
作者:Mahmood, Adeem; Alkhathlan, Hamad Z.; Parvez, Saima; Khan, Merajuddin; Shahzad, Sohail A.
作者机构:[Mahmood, Adeem; Alkhathlan, Hamad Z.; Khan, Merajuddin] King Saud Univ, Dept Chem, Coll Sci, Riyadh 11451, Saudi Arabia.; [Mahmood, Adeem; Shahzad, 更多
通讯作者:Mahmood, A
通讯作者地址:[Mahmood, A]King Saud Univ, Dept Chem, Coll Sci, Riyadh 11451, Saudi Arabia.
来源:MOLECULES
出版年:2015
卷:20
期:6
页码:9890-9905
DOI:10.3390/molecules20069890
关键词:lithiation; borylation; allylation; chelation
摘要:The lithiation of 2-(2,2-dimethyl-1,3-dioxolan-4-yl)ethyl diisopropylcarbamate (1) is achieved freely by sec-butyllithium in diethylether with high lk-diastereoselectivity: the bicyclic chelate complexes 3a and 3b are reacted with electrophiles to form optically active precursors 4a and 4b with >95% diastereoselectivity. In addition, tertiary diamines can undergo an external complexation in contest with the internal oxygen ligand, leading to improved stereoselectivities. The further reactions of lithiated carbamates with trans alkenyl-9-BBN derivatives after 1,2 metallate rearrangements, gave the key intermediate -substituted allylic boranes 7. Subsequent allylboration of aldehydes gave (Z)-anti-homoallylic alcohols 8 in good yield and excellent d.r.
收录类别:SCOPUS;SCIE
资源类型:期刊论文
原文链接:https://www.scopus.com/inward/record.uri?eid=2-s2.0-84938299444&doi=10.3390%2fmolecules20069890&partnerID=40&md5=7de58dd925a46da9fd1c0935158c8b98
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