A Second-Generation Formal Synthesis of (+)-Haplophytine

In this article, a Lewis acid mediated 1,4-addition/formal [3+2] cycloaddition reaction engaging functionalized beta-carboline and 1,4-benzoquinone has been demonstrated. Application of this developed technology facilitated the construction of the challenging C-9'-C-15 quaternary center linkage in the dimeric indole alkaloid, haplophytine, and enabled the preparation of an advanced key intermediate en route to the total synthesis of this historical natural product.