Total Synthesis of (±)-Aplykurodinone-1: Traceless Stereochemical Guidance
摘要:
The total synthesis of the highly degraded steroidal natural product, aplykurodinone-1 (1), has been accomplished. Key features include a one-flask hydrolysis/retro-aldol/iodolactonization sequence to excise the C-8 hydroxymethylene functionality with retention of stereochemistry and the stereoselective installation of the C-13 methyl group through hydrogenation with homogeneous catalyst.
Formal synthesis of degraded sterol (+)-aplykurodinone-1
摘要:
The formal synthesis of aplykurodinone-1 is accomplished starting from a suitably functionalized bicyclic lactone having the requisite cis-fused ring junction with a quaternary chiral center that was assembled following a Cp2TiCl-mediated radical cyclization protocol. Our synthetic route further elaborates implementation of Grubbs ring closing metathesis (RCM), Eschenmoser-Claisen rearrangement and iodo-lactonization reactions for the synthesis of the final tricyclic precursor of the target molecule. (C) 2015 Elsevier Ltd. All rights reserved.
H-Bonding Mediated Asymmetric Intramolecular Diels–Alder Reaction in the Formal Synthesis of (+)-Aplykurodinone-1
作者:Joon-Ho Lee、Cheon-Gyu Cho
DOI:10.1021/acs.orglett.8b03250
日期:2018.11.16
stereochemical control element governing the π-facial selectivity of intramolecularDiels–Alder (IMDA) reaction of an enone tethered 2-pyrone. In the IMDA process, the configuration at a stereogenic, hydroxyl bearing an α-carbon in the enone dienophile is conveyed in a highly effective manner through intramolecular hydrogen bonding with the enone carbonyl oxygen. The tricyclic lactone, generated in this process
A concise, stereoselective, and protecting-group-freetotalsynthesis of aplykurodinone-1 from Hajos–Parrish ketone was described. The synthetic approach features a sequence of aerobic allylic oxidation and elimination of alcohol 9. The key intermediate for this synthesis was formed by a stereoselective intramolecular radical cyclization.
作者:Gang Liu、Guangjian Mei、Runwen Chen、Haina Yuan、Zhen Yang、Chuang-chuang Li
DOI:10.1021/ol502220r
日期:2014.9.5
The concise total synthesis of aplykurodinone-1 with an unusual cis-fused hydrindane moiety has been accomplished without the need for any protecting group chemistry using a unique SmI2 mediated reductive cascade cyclization reaction and a direct cuprate mediated 1,4-addition. This work represents the first example of the use of a SmI2-mediated intramolecular cascade cyclization reaction between “halide
The tricyclic intermediate 2 has been synthesized in eight steps from known compound 6 in 20% overall yield. As such, this constitutes a highly efficient formalsynthesis of (±)-aplykurodinone-1. This synthesis features a unique, one-pot, intramolecular hetero-Pauson-Khand reaction (h-PKR)/desilylation sequence to expeditiously construct the tricyclic framework, providing valuable insights for expanding