A Highly Efficient Access to Spiroketals, Mono-unsaturated Spiroketals, and Furans: Hg(II)-Catalyzed Cyclization of Alkyne Diols and Triols
摘要:
Hg(II) salts are identified as highly efficient catalysts for the versatile construction of spiroketals from alkyne diols in aqueous conditions. Monounsaturated spiroketals and furans were accessed with equal ease when propargylic triols (or propargylic diols) were subjected to similar conditions. Even the semiprotected alkyne diols gave the corresponding spiroketals with the same ease in a cascade manner. The reactions are Instant and high yielding at ambient temperatures. Regioselectivity issues are well addressed.
Au(I)-Catalyzed Cyclization of Epoxyalkynes to Allylic Alcohol Containing Spiroketals and Application to the Total Synthesis of (−)-Alotaketal A
作者:Jaeyeon Lee、Jiheon Kim、Hee-Yoon Lee
DOI:10.1021/acs.orglett.0c01130
日期:2020.6.5
spiroketalization of epoxyalkynes accompanied by epoxide rearrangement into the corresponding allylic alcohol was developed for the construction of functionalized spiroketals. This new synthetic methodology for unsaturated spiroketals warranted a facile total synthesis of alotaketal A from carvone via a corresponding epoxyalkyne precursor.
Hg(II) salts are identified as highly efficient catalysts for the versatile construction of spiroketals from alkyne diols in aqueous conditions. Monounsaturated spiroketals and furans were accessed with equal ease when propargylic triols (or propargylic diols) were subjected to similar conditions. Even the semiprotected alkyne diols gave the corresponding spiroketals with the same ease in a cascade manner. The reactions are Instant and high yielding at ambient temperatures. Regioselectivity issues are well addressed.