A Transition-Metal-Free and Base-Mediated Carbene Insertion into Sulfur-Sulfur and Selenium-Selenium Bonds: An Easy Access to Thio- and Selenoacetals
作者:Dhanarajan Arunprasath、Govindasamy Sekar
DOI:10.1002/adsc.201600855
日期:2017.2.20
A transition‐metal‐free and base‐mediated carbene insertion across sulfur‐sulfur and selenium‐selenium bonds has been developed by employing N‐tosylhydrazone as a stable and safe carbene precursor. The ylide formation from carbene followed by Stevens rearrangement are considered to be the key steps. This thiol and selenol‐free protocol delivers thioacetals and selenoacetals in good to excellent yields
An efficient and mild method for thioacetalization of 2-alkynylbenzaldehydes in the
presence of a catalytic amount of silver triflate has been described. This reaction proceeded efficiently
to generate 2-alkynylbenzaldehydes thioacetals in good to excellent yields at room temperature within
short reaction time (no more than 30 min). This transformation was extremely easy to perform without
the need of using anhydrous solvent and inert atmosphere. Chemoselective thioacetalization of benzaldehyde in the presence
of acetophenone was also demonstrated.
Catalytic Cyclization of <i>o</i>-Alkynylbenzaldehyde Acetals and Thioacetals. Unprecedented Activation of the Platinum Catalyst by Olefins. Scope and Mechanism of the Reaction
作者:Itaru Nakamura、Gan B. Bajracharya、Huanyou Wu、Kengo Oishi、Yuya Mizushima、Ilya D. Gridnev、Yoshinori Yamamoto
DOI:10.1021/ja044603c
日期:2004.12.1
corresponding thioacetals proceeds without alkyl migration. Optimization of the catalytic system for the cyclization of o-alkynylbenzaldehyde acetals revealed an unknown activation effect: PtCl(2) was found to be a better catalyst for the cyclization of acetals in the presence of olefins than without. A similar catalytic system (PtCl(2)/benzoquinone) has been found to be appropriate for the cyclization