A chiral copper complex, generated from a C 2-symmetric bis(hydroxycamphorsulfonamide) ligand (8 mol%) and Cu(OTf)2, has been discovered to effect high enantioselectivities in the addition of alkynylzinc to a series of simple ketones. The alkynylation of a variety of aromatic and aliphatic ketones resulted in excellent yields and enantioselectivities (83-98% ee). Even when the loadings of the catalyst is 5 mol%, up to 94% ee was obtained.
一种由C2对称的双(羟基
樟脑磺酰胺)
配体(8摩尔%)和Cu(OTf)2生成的手性
铜配合物,已被发现能显著提高烷炔基
锌对一系列简单酮加成反应的立体选择性。对各种芳香族和脂肪族酮的炔基化反应,产率极高且具有优良的立体选择性(83-98% 对映体过量)。即使催化剂用量降至5摩尔%,也能获得高达94%的对映体过量。