Abstract
Abstract: Aryl or alkenyl iodides react regioselectively with allenes and hexaalkylditins in the presence of Pd(dba)2 to give substituted allylstannanes. A highly regio- and stereoselective method for the synthesis of 2-acylallylboronates based on a palladium-catalyzed three-component assembling of acyl chlorides, allenes and bis(pinacolato)diboron is described. Treatment of CR2R3=C=CH2 (R2 = R3 = Me; R2 = H, R3 = n-Bu; R3 = Ph; R3 = cyclohexyl; R3 = t-Bu) with acyl chlorides (R1COCl: R1 = p-MeOC6H4, p-NO2C6H4, C6H5, p-MeO2CC6H4, 1-naphthyl, 2-thienyl, 5-isooxazolyl, t-BuCH2, i-Bu, and Bn) and 3 in the presence of Pd(MeCN)2Cl2 in toluene at 80 °C gave 2-acylallylboronates in good to excellent yields. The acyl group adds to the allene without decarbonylation. In addition, no extra base is required to activate diboron in the reaction. These addition reactions are completely regioselective and for mono substituted allenes, the reactions also show extremely high E stereoselectivity. A mechanism based on a face-selective coordination of allenes to the palladium center is proposed to account for the present stereoselectivity. A highly regio- and stereoselective diboration of allenes was achieved with a catalytic amount of phosphine-free Pd complex and alkenyl or aryl iodide. Thus. Treatment of CR1R2=C=CH2 (R1 = R2 = Me; R1 = H, R2 = n-Bu; R2 = Ph; R2 = cyclohexyl; R2 = cyclopentyl, R2 = C6H5O, R2 = 2-IC6H4O, R2 = 4-IC6H4O) with bis(pinacolato)diborn in the presence of Pd(dba)2 (5 mol %) and 3-iodo-2-methyl-2-cyclohexen-1-one (5 mol %) in toluene at 80 oC gave products bearing both vinylic and allylic boron moieties in good to excellent yields. No diboration occurs in the absence of either a Pd complex or alkenyl iodide. In all cases, only the biboronic products with one boryl group adding to the middle carbon and the other to the nonsubstituted terminal carbon of the allene moiety were observed. This Pd-catalyzed reaction proceeds via a previously unknown mechanism involving the oxidative addition of an I-B bond to the palladium center instead of the oxidative addition of a B-B bond to metal. The substituent on the allene group shows little effect on the yield of biboronic product. A face-selective coordination of allene to the palladium center is proposed to account for the present stereoselectivity. A highly regioselective method for the synthesis of allylboronates based on a palladium-catalyzed three-component assembling of organic halides, allenes and bis(pinacolato)diboron is described. Treatment of dimethyl allene with organic iodides or bromides and diboron in the presence of Pd(dba)2 in DMF at 60 °C in the presence of excess base such as KOAc or K2CO3 gave allylboronates in good to excellent yields. These addition reactions are completely regioselective. In all cases, only the product which the organic group adding to the middle carbon and the boryl group to the nonsubstituted terminal carbon of the allene moiety were observed. These allylboronates show good reactivity to benzaldehyde to give homo allylic alcohols. 中文摘要 ----------------------------------------------------------------------------- i 英文摘要 ----------------------------------------------------------------------------- iii 圖目錄 ----------------------------------------------------------------------------- v 第一章 緒論 -------------------------------------------------------------- 1 參考文獻 ------------------------------------------------------------- 28 第二章 鈀金屬錯合物催化1,2-雙烯與有機鹵化物及有機雙錫試劑的偶合反應---多取代丙烯基錫試劑的合成 前言 ------------------------------------------- 35 結果與討論 ------------------------------------------- 41 結論 ------------------------------------------- 58 實驗部分及光譜資料 ------------------------------------------- 59 參考文獻 ------------------------------------------- 79 附錄1H-NMR光譜圖 ------------------------------------------- 83 第三章 鈀金屬錯合物催化1,2-雙烯與有機醯氯化物及有機雙硼試劑的偶合反應---醯基丙烯基硼試劑的合成 前言 ------------------------------------------- 107 結果與討論 ------------------------------------------- 111 結論 ------------------------------------------- 129 實驗部分及光譜資料 ------------------------------------------- 131 參考文獻 ------------------------------------------- 147 附錄1H-NMR光譜圖 ------------------------------------------- 149 第四章 鈀金屬錯合物催化有機雙硼試劑加成到1,2-雙烯之雙硼化反應---丙烯基雙硼試劑的合成 前言 ------------------------------------------- 169 結果與討論 ------------------------------------------- 176 結論 ------------------------------------------- 206 實驗部分及光譜資料 ------------------------------------------- 207 參考文獻 ------------------------------------------- 227 附錄1H-NMR光譜圖 ------------------------------------------- 231 第五章 鈀金屬錯合物催化有機鹵化物與1,2-雙烯及有機雙硼試劑的偶合反應---多取代丙烯基硼試劑的合成 前言 ------------------------------------------- 241 結果與討論 ------------------------------------------- 241 結論 ------------------------------------------- 254 實驗部分及光譜資料 ------------------------------------------- 255 參考文獻 ------------------------------------------- 270 附錄1H-NMR光譜圖 ------------------------------------------- 271