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

Brockton Keen; Christina Cong; Alberto Castanedo; Geraint H.M. Davies; Robert R. Knowles; Huw M.L. Davies

doi:10.1021/acs.orglett.5c00054

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

Brockton Keen, Christina Cong, Alberto Castanedo, Geraint H.M. Davies, Robert R. Knowles, Huw M.L. Davies

Research output: Contribution to journal › Article › peer-review

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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.

Original language	English (US)
Pages (from-to)	1673-1678
Number of pages	6
Journal	Organic letters
Volume	27
Issue number	7
DOIs	https://doi.org/10.1021/acs.orglett.5c00054
State	Published - Feb 21 2025

All Science Journal Classification (ASJC) codes

Biochemistry
Physical and Theoretical Chemistry
Organic Chemistry

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

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.",

author = "Brockton Keen and Christina Cong and Alberto Castanedo and Davies, \{Geraint H.M.\} and Knowles, \{Robert R.\} and Davies, \{Huw M.L.\}",

note = "Publisher Copyright: {\textcopyright} 2025 The Authors. Published by American Chemical Society.",

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doi = "10.1021/acs.orglett.5c00054",

language = "English (US)",

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T1 - Stereoselective Synthesis of Highly Functionalized Bicyclo[2.1.0]pentanes by Sequential [2 + 1] and [2 + 2] Cycloadditions

AU - Keen, Brockton

AU - Cong, Christina

AU - Castanedo, Alberto

AU - Davies, Geraint H.M.

AU - Knowles, Robert R.

AU - Davies, Huw M.L.

PY - 2025/2/21

Y1 - 2025/2/21

N2 - 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.

AB - 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.

UR - https://www.scopus.com/pages/publications/85217562989

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AN - SCOPUS:85217562989

SN - 1523-7060

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JO - Organic letters

JF - Organic letters

IS - 7

ER -

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

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