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Palladium/TY-Phos-Catalyzed Asymmetric Heck/Tsuji-Trost Reaction of o-Bromophenols with 1,3-Dienes

Youshao Tu, Bing Xu, Qian Wang, Honglin Dong, Zhan-Ming Zhang* and Junliang Zhang*

*Department of Chemistry, Fudan University, Shanghai 200438, P. R. China, Email: zhanmingzhangfudan.edu.cn, junliangzhangfudan.edu.cn

Y. Tu, B. Xu, Q. Wang, H. Dong, Z.-M. Zhang, J. Zhang, J. Am. Chem. Soc., 2023, 145, 4378-4383.

DOI: 10.1021/jacs.2c12752



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Abstract

A highly enantioselective Pd/TY-Phos-catalyzed Heck/Tsuji-Trost reaction of o-bromophenols with various 1,3-dienes provides chiral substituted 2,3-dihydrobenzofurans with excellent regio- and enantiocontrol, high functional group tolerance, and easy scalability. The construction of optically pure natural products (R)-tremetone and fomannoxin is highlighted.

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General procedure for palladium-catalyzed Heteroannulation

In an oven-dried 25 mL Schlenk tube equipped with a stir bar, Pd2(dba)3•CHCl3 (3 or 5 mol%), TY-Phos (12 or 20 mol%), PhONa (2 equiv.), substituted ortho-bromophenol (0.1 or 0.3 mmol), 1,3-diene (3 or 5 equiv). The flask was evacuated and refilled with nitrogen. Then 2 mL DCM was added to the tube under nitrogen atmosphere, and stirred at 40°C for 48-72 h. After the reaction was complete (monitored by TLC), the filtrate was evaporated to dryness under reduced pressure and the crude residue was purified by flash column chromatography on silica gel (PE:EtOAc = 50:1) to afford the desired product.


Key Words

Heck reaction, Tsuji-Trost allylation, 2,3-dihydrobenzofurans


ID: J48-Y2023