Lead-mediated highly diastereoselective allylation of aldehydes with cyclic allylic halides

• Main Authors: Cheng, Bu-Qing, Zhao, Shi-Wen, Song, Xuan-Di, Chu, Xue-Qiang, Rao, Weidong, Loh, Teck-Peng, Shen, Zhi-Liang
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2021
• Subjects: Science::Chemistry; Donor-acceptor Cyclopropanes; Aqueous-media
• Online Access: https://hdl.handle.net/10356/147494
• Institution: Nanyang Technological University

Lead was found to efficiently mediate the allylation reactions of carbonyl compounds with cyclic allylic halides in the presence of stoichiometric amounts of lithium chloride and a catalytic amount of GaCl3 (20 mol %), leading to the desired homoallylic alcohols in modest to high yields with excellent diastereocontrol (>99:1 syn/anti) and good functional group tolerance. In contrast, the use of either 2-pyridinecarboxaldehyde as the carbonyl substrate or ( E)-cinnamyl bromide as the allylating agent produced the corresponding product with reversed diastereoselectivity (>99:1 anti/syn).