Bioinspired total synthesis of katsumadain A by organocatalytic enantioselective 1,4-conjugate addition

• Yongguang Wang,
• Ruiyang Bao,
• Shengdian Huang and
• Yefeng Tang

Beilstein J. Org. Chem. 2013, 9, 1601–1606, doi:10.3762/bjoc.9.182

• ; organocatalytic 1,4-conjugate addition; Introduction 2-Pyranone is a privilege structure that is often present in natural products and pharmaceuticals, many of which exhibit diverse molecular architectures and biological profiles [1][2]. For example, katsumadain A (1) and B (2), which were isolated from Alpinia

• katsumadain A, we then moved towards the alternative approach as described in Scheme 1. We envisioned that in this scenario an organocatalytic 1,4-conjugate addition [24][25][26][27] between 3 and 7 would circumvent both the reactivity and selectivity issues, which we have struggled with in the aforementioned

• studies. To validate this hypothesis, we performed a systematic investigation of the organocatalytic 1,4-conjugate addition by examining various reaction parameters, including organocatalyst, acid additive, solvent temperature, and reaction temperature (Table 1). The first reaction was performed by