Divergent Strategies for the π-Extension of Heteroaryl Halides Using Norbornadiene as an Acetylene Synthon
作者:Siyeon Jeong、Eunmin Kim、Minkyu Kim、Ye Ji Hwang、Birakishore Padhi、Jonghoon Choi、Yunho Lee、Jung Min Joo
DOI:10.1021/acs.orglett.0c03732
日期:2020.12.18
reactions of five-membered heteroaryl halides and norbornadiene (NBD) were developed. Either direct addition of (benzo)azoles or 2:1 annulation was achieved depending on the propensity of the intermediate complex to undergo palladacycle formation, determined by the nature and substitution pattern of the heteroarene. The obtained exo- and cis-diheteroaryl norbornenes underwent epimerization and retro-Diels–Alder
A new application of silicon Grignard reagents in C(sp3)−Si bond formation is reported. With the aid of BF3⋅OEt2, these siliconnucleophiles add across alkenes activated by various azaaryl groups under copper catalysis. An enantioselective version employing benzoxazole‐activated alkenes as substrates and a CuI‐josiphos complex as catalyst has been developed, forming the C(sp3)−Si bond with good to