Stereoselective Synthesis of Highly Functionalized Bicyclo[2.1.0]pentanes by Sequential [2 + 1] and [2 + 2] Cycloadditions

2025/02/10 by Brockton Keen, Christina Cong, Alberto Castanedo +3 · 1 voice · 1 citation
Chemistry · #Cyclopropane Reaction Mechanisms #Catalytic C–H Functionalization Methods #Catalytic Alkyne Reactions

paper · pdf · doi:10.1021/acs.orglett.5c00054

openalex publication_date 2025/02/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/22

Abstract

This study describes a method for the stereoselective synthesis of highly functionalized bicyclo[2.1.0]pentanes (housanes). The approach utilizes a two-step sequence, a silver- or gold-catalyzed cyclopropenation of alkynes followed by an intermolecular [2 + 2] photocycloaddition reaction with electron-deficient alkenes. The cyclopropenation is an established reaction of aryldiazoacetates. A regioselective [2 + 2] cycloaddition of the cyclopropane was developed using blue LED irradiation, a commercially available photocatalyst as a triplet-sensitizer, and low reaction temperature (-40 °C). The [2 + 2] cycloaddition is highly diastereoselective, and when enantioenriched cyclopropenes are used, it proceeds with enantioretention.

Cited by

• Divergent housane synthesis via intramolecular [2 + 2] cycloaddition of 1,4-dienes

Discussions

• Nice very fast way to housanes by Knowles, Davies and co-workers in OL doi.org/10.1021/acs.... [bsky, 3 points, 0 comments]

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