过渡金属催化的2,3-联烯酸环化合成γ-丁烯酸内酯

γ-丁烯酸内酯是一类具有重要潜在活性的化合物.发展了二价钯催化的2,3-联烯酸和(ω-1)-烯基卤化物的偶联关环反应.反应经过了二价钯催化的氧钯化-碳钯化,重复的去钯氢化/钯氢化及β-脱卤钯化反应.同时还发展了两种联烯之间的二聚环化反应,两分子2,3-联烯酸的反应生成二丁烯酸内酯,2,3-联烯酸与1,2-联烯酮反应则生成呋喃基取代的γ-丁烯酸内酯.

Synthesis of Butenolides via Transition Metal-Catalyzed Cyclization Reaction of 2,3-Allenoic Acids

Butenolides are a class of compounds of current interest due to their occurrence in natural products and the potential broad range of biological activities of natural and unnatural products. During the course of our study on transition metal-catalyzed cyclization reaction of 2,3-allenoic acids, we have developed palladium (Ⅱ)-catalyzed reaction of 2, 3-allenoic acids with (ω-1)-alkenyl halides to introduce sp3-hybridized carbon atoms at the β position of butenolides. In this reaction, we observed a new Pd (Ⅱ)-catalytic cycle which combines carbopalladation with repeated dehydropalladation/hydropalladation-β-dehalopalladation. Furthermore, a new area of oxidative cyclization-dimerization reaction of two functionalized allenes has been established. In this area, we have developed oxidative dimeric cyclization reaction of 2, 3-allenoic acids to afford bi-butenolides. Moreover, oxidative cyclization-dimerization reaction of 2, 3-allenoic acids with 1,2-allenyl ketones was also established to furnish interesting compounds with two different cycles in a single step.