Synthesis of Functionalized Medium-Sized trans-Cycloalkenes by 4π Electrocyclic Ring Opening/Alkylation Sequence

Area of Science:

• Organic Chemistry
• Synthetic Chemistry

Background:

• Medium-sized rings present synthetic challenges.
• Trans-cycloalkenes (TCAs) are valuable structural motifs.

Purpose of the Study:

• To develop an efficient synthetic route to functionalized TCAs.
• To demonstrate central-to-planar chirality transfer in TCA synthesis.

Main Methods:

• Synthesis initiated from simple cycloalkanones.
• Key steps include enol silyl ether formation, [2+2] cycloaddition, and a domino electrocyclic ring opening/alkylation.
• Utilized enantiomerically enriched cyclobutenes for chirality transfer.

Main Results:

• Successfully synthesized functionalized medium-sized TCAs.
• Established a novel domino reaction sequence for TCA formation.
• Achieved the first example of central-to-planar chirality transfer to TCAs.

Conclusions:

• The developed method provides facile access to functionalized TCAs.
• This work expands the synthetic toolbox for medium-sized carbocycles.
• Demonstrated a new strategy for constructing chiral molecules with planar chirality.