A magnesium-catalyzed regiodivergent C–Obond cleavage protocol is presented. Readily available magnesium catalysts achieve the selective hydroboration of a wide range of epoxides and oxetanes yielding secondary and tertiary alcohols in excellent yields and regioselectivities. Experimental mechanistic investigations and DFT calculations provide insight into the unexpected regiodivergence and explain
Rhodium-Catalyzed Asymmetric Conjugate Addition of Arylboroxines to Borylalkenes: Asymmetric Synthesis of β-Arylalkylboranes
作者:Keigo Sasaki、Tamio Hayashi
DOI:10.1002/anie.201004980
日期:2010.10.25
Asymmetricconjugateaddition of arylboroxines to borylalkenes proceed in the presence of a chiral bisphosphine/rhodium complex as a catalyst to give chiral β‐arylalkylboranes with high enantioselectivities (see scheme). [O]=H2O2/NaOH.
在手性双膦/铑配合物作为催化剂的存在下,芳基硼氧烷与硼烷基烯烃的不对称共轭加成反应产生具有高对映选择性的手性β-芳基烷基硼烷(参见方案)。[O] = H 2 O 2 / NaOH。
Synthesis of (<i>E</i>)-α,β-Unsaturated Carbonyls<i>via</i>Silver-Catalyzed Tandem Epoxide Rearrangement/Intermolecular Carbonyl- Heteroalkyne Metathesis
stereoselective method for the synthesis of (E)‐α,β‐unsaturated carbonyls has been developed via a silver‐catalyzed tandem epoxide rearrangement/intermolecular carbonyl‐heteroalkyne metathesis. Various heteroalkynes including ynol ethers, ynamides, and thioalkynes work well for this transformation, leading to the production of (E)‐α,β‐unsaturatedesters, amides, and thioesters in moderate to excellent