A highly practical synthesis of natural PGE1, Δ2-trans-PGE1 and 2,2,3,3-tetradehydro-PGE1 via two-component coupling process using zinc-copper reagents
Benzannulation of Triynes to Generate Functionalized Arenes by Spontaneous Incorporation of Nucleophiles
作者:Rajdip Karmakar、Sang Young Yun、Jiajia Chen、Yuanzhi Xia、Daesung Lee
DOI:10.1002/anie.201412468
日期:2015.5.26
The thermal reaction of ester‐tethered 1,3,8‐triynes provides novel benzannulation products with concomitant incorporation of a nucleophile. Evidence suggests that this reaction proceeds via an allene‐enyne intermediate generated by an Alder‐ene reaction in the first step. Depending on the substituent of the alkyne moiety on the allene‐enyne intermediate, the subsequent transformation can take one
A general protocol for the title transformation has been achieved and is applicable to a wide range of acyclic 1,3‐dienes and cyclic alkyne—Co2(CO)6} complexes leading to various types of benzannulated medium‐sized cyclic compounds after oxidative work up (see scheme; DDQ=2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone). Interestingly, the [4+2] cycloaddition proceeded preferentially over the Pauson–Khand