Expanding the Scope of Enantioselective FerroPHANE-Promoted [3+2] Annulations with α,β-Unsaturated Ketones
作者:Nathalie Pinto、Mathilde Neel、Armen Panossian、Pascal Retailleau、Gilles Frison、Arnaud Voituriez、Angela Marinetti
DOI:10.1002/chem.200901893
日期:2010.1.18
The planar chiral 2‐phospha[3]ferrocenophane I has been shown to be the first efficient nucleophilic organocatalyst for the enantioselective synthesis of cyclopentenylphosphonates, through [3+2] cyclizations between diethyl allenylphosphonate and α,β‐unsaturated ketones. The same catalyst has also been applied to the highly enantioselective [3+2] cyclizations of allenic esters with dibenzylideneacetone
平面型手性2-磷[3]二茂铁卟啉I已被证明是环戊烯基膦酸酯对映选择性合成的第一个有效亲核有机催化剂,它通过二乙基烯丙基膦酸酯和α,β-不饱和酮之间的[3 + 2]环化反应来实现。同样的催化剂也已用于烯丙基酯与二亚苄基丙酮和类似的双烯酮的高度对映选择性[3 + 2]环化反应,从而生成具有单环或螺环结构的官能化环戊烯(ee 84–95%)。已经表明,所得环戊烯中的残留烯酮功能可参与随后的环化步骤,以提供空前的C 2。对称双环戊烯酮。为了深入了解FerroPHANE I作为手性催化剂在[3 + 2]环化反应中的行为,已通过DFT方法计算了主要的膦-丙二烯加合物在能量上最受青睐的异构体。强调了可能控制手性诱导过程的因素。