A Synthetic Strategy for Polyfunctionalized Bicyclo[3.3.1]nonanes Based on a Tandem Three-Component [3 + 2] Cycloaddition of α-Cinnamoyl Ketene-S,S-acetals with Oxalyl Chloride
摘要:
A simple and highly efficient three-component reaction of the readily available alpha-cinnamoyl ketene-S,S-acetals 1 with oxalyl chloride has been developed and the corresponding gamma-alkylidenebutenolides 2 were obtained stereospecifically in excellent yields under very mild conditions. On the basis of this reaction, a series of highly functionalized bicyclo[3.3.1]nonanes 3 were constructed in good to high yields in an atom-economic manner with good diastereoselectivity via a BF(3)center dot OEt(2)-mediated novel tandem double cyclization of gamma-alkylidenebutenolides 2 under very mild conditions.
Copper(II)‐catalyzed Domino Reaction of the Acyclic Ketene‐(
<i>S</i>
,
<i>S</i>
)‐Acetals with Diazo Compounds: Convenient Synthesis of Poly‐substituted Thiophenes
the acyclic ketene‐(S,S)‐acetals and diazo compounds has been successfully developed. This reaction proceeds through a sequential formation of electrophilic copper carbenoid, sulfur ylide and subsequent C−S bond coupling and cleavage. Notably, the domino reaction features broad the readily available acyclic ketene‐(S,S)‐acetals scope and provides a new strategy for the synthesis of poly‐substituted