A vicarious, one-pot synthesis of benzo- and naphthofurans: Applications to the syntheses of stereumene B and paeoveitols
作者:Showkat Rashid、Bilal A. Bhat、Goverdhan Mehta
DOI:10.1016/j.tetlet.2019.03.037
日期:2019.4
deviation during attempted Tanabe γ-lactone annulation on 4-hydroxycyclohexanones has led to a general, one-potsynthesis of benzofurans and naphtho[2,3–b]furans from readily assembled precursors. The utility of this adaptable methodology has been demonstrated through concise syntheses of natural products, stereumene B, paeoveitol D and (±)-paeoveitol.
有趣的是,在尝试在4-羟基环己酮上进行田边γ-内酯环化过程中出乎意料的偏差,导致了从易组装的前体中普遍进行一锅法合成苯并呋喃和萘并[2,3- b ]呋喃的过程。通过天然产物,立体异构体B,paeoveitol D和(±)-paeoveitol的简明合成,已证明了这种适应性方法的实用性。
catalytic asymmetric total synthesis of (+)- and (−)-paeoveitol has been accomplished in 42% overall yield via a biomimetic hetero-Diels–Alder reaction. The chiral phosphoric acid catalyzed hetero-Diels–Alder reaction showed excellent diastereo- and enantioselectivity (>99:1 dr and 90% ee); two rings and three stereocenters were constructed in a single step to produce (−)-paeoveitol on a scale of 452
A four-step total synthesis of paeoveitol (1), a recently disclosed norditerpene natural product from Paeonia vetchii, is reported. This highly concise synthetic route was guided by biosynthetic considerations and enabled by an unusual intermolecular ortho-quinone methide [4 + 2]-cycloaddition reaction, which proceeded with excellent regio- and diastereoselectivity. Density functional theory (DFT) calculations point to a crucial intermolecular hydrogen bond and pi-pi stacking interaction that govern selectivity in this process.