Four-Step Total Synthesis of (+)-Yaoshanenolides A and B

Sagar S Thorat; Megha N Palange; Ravindar Kontham

doi:10.1021/acsomega.8b00701

Four-Step Total Synthesis of (+)-Yaoshanenolides A and B

ACS Omega. 2018 Jun 28;3(6):7036-7045. doi: 10.1021/acsomega.8b00701. eCollection 2018 Jun 30.

Authors

Sagar S Thorat^{1

2}, Megha N Palange^{1

2}, Ravindar Kontham^{1

2}

Affiliations

¹ Division of Organic Chemistry, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India.
² Academy of Scientific and Innovative Research (AcSIR), New Delhi 110025, India.

Abstract

A highly concise bioinspired four-step total synthesis of yaoshanenolides A and B possessing tricyclic spirolactone with an unusual 5'H-spiro-[bicyclo[2.2.2]-oct[2]ene-7,2'-furan]-5'-one scaffold is reported. This synthesis features high-yielding aldol-type addition of γ-butyrolactone on to the aldehyde, exocyclic olefination of lactone derivative using Eschenmoser's salt, and highly facial- and endo-selective [4 + 2]-cycloaddition of fully functionalized 5-methylene-2(5H)-furanone with natural R-(-)-α-phellandrene. The approach allows access to yaoshanenolides A and B in four linear steps in 11 and 13% overall yield.