Tandem Cyclization−Cycloaddition Behavior of Rhodium Carbenoids with Carbonyl Compounds: Stereoselective Studies on the Construction of Novel Epoxy-Bridged Tetrahydropyranone Frameworks
作者:Sengodagounder Muthusamy、Srinivasarao Arulananda Babu、Chidambaram Gunanathan、Bishwajit Ganguly、Eringathodi Suresh、Parthasarathi Dastidar
DOI:10.1021/jo0256134
日期:2002.11.1
Alternatively, the cycloaddition of carbonyl ylides with alpha,beta-unsaturated ketones 27/28 provided both the C=O and C=C cycloaddition products. The cycloaddition of carbonyl ylides with carbonyl compounds occurred in good yields and was found to be highly regio- and stereoselective. Single-crystal X-ray analyses were performed to unambiguously establish the structure and stereochemistry of the novel
本文介绍了在羰基化合物存在下,由α-重氮酮产生的羰基串联反应的研究和立体选择性研究。铑类胡萝卜素的分子内环化反应生成了瞬态的五元或六元环羰基内酯偶极子,该偶极子与各种双极性亲子化合物(例如芳香族醛15,α,β-不饱和醛18/24,α)有效地进行了1,3-偶极环加成反应。 ,β-不饱和酮27/28/31和二烯酮34。瞬态羰基酰化物与各种芳族醛进行环加成反应,以非对映选择性的方式提供了多种环氧桥联的四氢吡喃酮环系统。羰基化物与α的环加成,β-不饱和醛18/24或二烯酮34以化学选择性的方式提供了C = O加成产物,尽管在上述双亲性化合物中存在C = C键。备选地,用α,β-不饱和酮27/28对羰基酰基进行的环加成提供了C = O和C = C的环加成产物。羰基化合物与羰基化合物的环加成反应收率很高,并且被发现具有很高的区域选择性和立体选择性。进行了单晶X射线分析,以明确确定新型环氧桥联的四氢吡喃酮环系统35a