Ruthenium-Catalyzed C−C Bond Forming Transfer Hydrogenation: Carbonyl Allylation from the Alcohol or Aldehyde Oxidation Level Employing Acyclic 1,3-Dienes as Surrogates to Preformed Allyl Metal Reagents
作者:Fumitoshi Shibahara、John F. Bower、Michael J. Krische
DOI:10.1021/ja801213x
日期:2008.5.1
Under the conditions of ruthenium-catalyzed transfer hydrogenation, commercially available acyclic 1,3-dienes, butadiene, isoprene, and 2,3-dimethylbutadiene, couple to benzylic alcohols 1a-6a to furnish products of carbonyl crotylation 1b-6b, carbonyl isoprenylation 1c-6c, and carbonyl reverse 2-methyl prenylation 1d-6d. Under related transfer hydrogenation conditions employing isopropanol as terminal
市售无环1,3-二烯、丁二烯、异戊二烯、2,3-二甲基丁二烯在钌催化转移氢化条件下与苄醇1a-6a偶联,得到羰基巴豆酰化产物1b-6b、羰基异戊二烯化产物1c -6c,和羰基反向2-甲基异戊二烯化1d-6d。在使用异丙醇作为末端还原剂的相关转移氢化条件下,异戊二烯与醛7a-9a偶联,提供相同的羰基异戊二烯化1c-3c产物。因此,在不存在预先形成的烯丙基金属试剂的情况下,由醇或醛的氧化水平实现羰基烯丙基化。还证明了与脂肪醇(异戊二烯至 1-壬醇,分离产率 65%)和烯丙醇(异戊二烯至香叶醇,分离产率 75%)的偶联。同位素标记研究证实了一种涉及反应物醇或牺牲醇 (i-PrOH) 供氢的机制。