Nitro versus nitro: 4‐Nitro‐5‐styrylisoxazoles were used as masked α,β‐unsaturated carboxylic acids in the titled catalytic asymmetric transformation. The 4‐nitroisoxazole core acts as an activator of the conjugated alkene and a latent carboxylate functionality. The reaction proceeded with 5 mol % of a readily prepared phase‐transfer catalyst at room temperature with remarkable diastereo‐ and enantioselectivity
硝基与硝基:在标题为催化不对称转化中,使用4‐Nitro‐5‐styrylisoxazoles作为掩蔽的α,β‐不饱和
羧酸。
4-硝基异恶唑核心充当共轭烯烃的活化剂和潜在的
羧酸盐官能团。反应在室温下以5摩尔%的现成相转移催化剂进行,反应具有非对映选择性和对映选择性(参见方案)。