Axial-to-Central Chirality Transfer for Construction of Quaternary Stereocenters via Dearomatization of BINOLs

Abstract

All-carbon quaternary stereocenters are versatile building blocks, and their asymmetric construction has attracted much attention. Herein, we disclose an axial-to-central chirality transfer strategy for the synthesis of chiral quaternary stereocenters via dearomatization of (S)-BINOLs. The reaction proceeded smoothly with a wide range of propargyl carbonates to afford chiral spiro-compounds in high yields with excellent enantioselectivities. In addition, the strategy was extended to kinetic resolution of rac-BINOLs albeit with moderate s value.

Concise Synthesis of 7-Deoxypsammaplysins K and O and 7-Deoxyceratinamide A by 1,3-Dipole Cycloaddition

“…Because the reaction could be pH-dependent, , we investigated the reaction sensitivity to pH. We first tested the reactions under nearly neutral conditions using Na 2 HPO 4 /NaH 2 PO 4 (pH 7.2) and neutral alumina Al 2 O 3 (pH 6.5–7.5) as additives.…”

Exploiting the Versatility of Palladium Catalysis: A Modern Toolbox for Cascade Reactions

“…He and coworkers developed an enantioselective protocol involving axial to central chirality transfer to construct spirocompounds by dearomatization of (S)-BINOL (Scheme 40). [63] BINOL 249 reacts with allenyl Pd Alternatively, cyclization can also result in 250 d, which can undergo isomerization to afford the desired product 251 in 49-98 % yield and > 99 % ee.…”

Six-membered ring systems: with O and/or S atoms

“…Replacing isoxazolones by barbiturates, various spirobarbiturate chromans are obtained (19T130752). Asymmetric synthesis of spironaphthalenone benzo[f]chromans is accomplished through dearomatization of (S)-1,1 0 -bisnaphth-2-ols [(S)-BINOLs] with a-alkyl/arylpropargyl carbonates using a palladium complex in DCE at 50 C (19OL9188).…”