Tandem Nitroaldol−Dehydration Reactions Employing the Dianion of Phenylsulfonylnitromethane<sup>1</sup>
作者:Peter A. Wade、James K. Murray,、Sharmila Shah-Patel、Bruce A. Palfey、Patrick J. Carroll
DOI:10.1021/jo0000170
日期:2000.11.1
been implicated in the formation of bis(alpha-nitrosulfones), Michael adducts of phenylsulfonylnitromethane. Three diastereomers (1R,2s,3S, 1R,2r,3S, and 1R,3R/1S,3S) have been identified for the bis(alpha-nitrosulfones) obtained in these reactions. In the case of acetaldehyde, condensation with the dilithium salt of phenylsulfonylnitromethane afforded only bis(alpha-nitrosulfones). The main product
苯磺酰基硝基甲烷(1)与超过2摩尔当量的LDA反应,得到苯磺酰基硝基甲烷的二锂盐。该二锂盐与直链醛的缩合反应很容易发生,但最初的硝基羟醛脱水后得到未共轭的β,γ-不饱和α-硝基砜,收率为52-88%。证据表明,在中性pH值下,β,γ-不饱和α-硝基砜可以与结合的α,β-不饱和α-硝基砜平衡。通常不利的α,β-不饱和α-硝基砜与苯基磺酰基硝基甲烷的双(α-硝基砜)迈克尔加合物的形成有关。对于在这些反应中获得的双(α-亚硝基砜),已鉴定出三种非对映异构体(1R,2s,3S,1R,2r,3S和1R,3R / 1S,3S)。如果是乙醛,与苯基磺酰基硝基甲烷的二锂盐缩合仅得到双(α-硝基砜)。主要产物(三种非对映异构体)是衍生自苯磺酰基硝基甲烷的迈克尔加成反应的双(α-硝基砜),次要产物暂定是衍生自二聚化的双(α-硝基砜)。在丙醛与苯磺酰基硝基甲烷的二锂盐的反应中还形成了不稳定的β-胺,它是二异丙胺