The first highly enantioselective allylic–allylic alkylation of α,α‐dicyanoalkenes and Morita–Baylis–Hillman carbonates by dualcatalysis of (DHQD)2AQN and (S)‐BINOL has been investigated. Excellent stereoselectivities have been achieved for a broad spectrum of substrates (d.r. > 99:1, up to 99 % ee). The multifunctional allylic products could be efficiently converted to a range of complex chiral cyclic
Asymmetric Allylic Monofluoromethylation and Methylation of Morita-Baylis-Hillman Carbonates with FBSM and BSM by Cooperative Cinchona Alkaloid/FeCl2 Catalysis
yields with high ee values (see scheme, (DHQD)2AQN=hydroquinidine(anthraquinone‐1,4‐diyl) diether). The cooperativecatalysis of bis(cinchona alkaloid) and Lewis acid, particularly FeCl2, was effective for these transformations and gave the monofluoromethylation products with over 90 % ee and methylation products with up to 97 % ee.
An efficient and catalyst-free synthesis of trisubstituted allylic sulfones through an allylic sulfonylation reaction of Morita-Baylis-Hillman (MBH) carbonates with sodium sulfinates has been developed. Under the optimized reaction conditions, a series of trisubstituted allylic sulfones were rapidly prepared in good to excellent yields (71%–99%) with good to high selectivity (Z/E from 79:21 to >99:1). Compared with known synthetic methods, the current protocol features mild reaction temperature, high efficiency and easily available reagents.
Asymmetric allylic amination of Morita–Baylis–Hillman (MBH) adducts with simple aromatic amines is successfully realized by nucleophilic amine catalysis. A range of substituted α-methylene-β-arylamino esters is accessed in moderate to high yields (up to 88%) and with excellent enantioselectivities (up to 97% ee). Inorganic fluorides are found to be able to improve the enantioselectivity of the allylic
Asymmetric allylicsubstitution of Morita–Baylis–Hillman (MBH) carbonates with less-nucleophilic phenols mediated by nucleophilic amine catalysis was successfully developed. A variety of substituted aryl allyl ethers were afforded with moderate to high yields with excellent enantioselectivities. The chiral MBH alcohol could be easily accessed from the corresponding aryl allyl ether.