copolymerization of a dirhodium(II) complex-containing monomer with styrene and 1,6-bis(4-vinylbenzyloxy)hexane as a flexible cross-linker. The polymer-supported chiral fluorinated dirhodium(II) complex catalyzed the amination of silylenolethers with [N-(2-nitrophenylsulfonyl)imino]phenyliodinane (NsNIPh) to provide α-amino ketones in high yields with high levels of enantioselectivity and could be used
Hypervalent Iodine(III)‐Catalysed Enantioselective α‐Acetoxylation of Ketones
作者:Tobias Hokamp、Thomas Wirth
DOI:10.1002/chem.202000927
日期:2020.8.17
An enantioselective catalytic synthesis of α‐acetoxylated ketones through I(I)/I(III) catalysis using a resorcinol/lactamide‐based chiral iodoarene is reported. Catalyst turnover by in situ generation of the active iodine(III) derivative is achieved by oxidation with mCPBA in the presence of acetic acid. The prior transformation of ketones to easily accessible acetyl enol ethers is beneficial and yields
catalyst for enantioselective aminations of silyl enol ethers derived from acyclic ketones or alpha,beta-enones with [N-(2-nitrophenylsulfonyl)imino]phenyliodinane (NsN=IPh), providing N-(2-nitrophenylsulfonyl)-alpha-amino ketones in high yields and with enantioselectivities of up to 95% ee. The effectiveness of the present catalytic protocol has been demonstrated by an asymmetric formal synthesis of (-)-metazocine
Michael reactionbetween silyl enolates and 0',/3-unsaturated carbonyl compounds by using a catalytic amount of Lewis base such as lithium alkoxide in DMF proceeds smoothly to afford the corresponding Michael-adducts in good yields with moderate to high diastereoselectivities. This reaction can be reasonably explained by considering an alkoxide anion-initiated autocatalytic process.