Bu3SnH-mediated 5-exo selective radical cyclization of N-vinyl-α,β-unsaturated amides leading to γ-lactams
作者:Takashi Okitsu、Miho Saito、Osamu Tamura、Hiroyuki Ishibashi
DOI:10.1016/j.tet.2005.06.116
日期:2005.9
and a catalytic amount of AIBN in boiling benzene caused 5-exo cyclization of allylic O-stannyl ketyl radicals generated by addition of Bu3Sn· on the amide-oxygen atoms to provide γ-lactams 2a–h after acidic workup. When enamide 1d was treated with Bu3SnH in the presence of AIBN followed by aldehydes 3a–d, sequential radical cyclization and aldol reactions occurred to afford anti-adducts 4a–d and syn-adducts
用Bu 3 SnH和沸点苯中催化量的AIBN处理N-乙烯基-α,β-不饱和酰胺1a - h会导致在苯上加Bu 3 Sn·产生烯丙基O-锡烷基酮基自由基的5外环化。酸性处理后,酰胺-氧原子可提供γ-内酰胺2a - h。当在AIBN存在下,先用Bu 3 SnH对Enamide 1d进行处理,然后再进行醛3a - d的处理时,依次发生自由基环化和醛醇缩合反应,得到抗加合物4a - d和SYN -adducts图5a,b。