Efficient preparation of TMSCCl2Br and its use in dichlorocyclopropanation of electron deficient alkenes

The reaction of excess TMSCl and LiCCl2Br at low temperature is a technically simple high yield route to TMSCCl2Br. The latter is a stable source of the dichlorobromomethide carbanion, which undergoes 1,4-addition with cyclic nitroalkenes and (E)-fumarates leading to dichlorocyclopropanes after brom...

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Main Authors: Lee, Darren S., Durán-Peña, Maria Jesus, Burroughs, Laurence, Woodward, Simon
Format: Article
Published: Wiley-VCH Verlag 2016
Subjects:
Online Access:https://eprints.nottingham.ac.uk/32995/
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author Lee, Darren S.
Durán-Peña, Maria Jesus
Burroughs, Laurence
Woodward, Simon
author_facet Lee, Darren S.
Durán-Peña, Maria Jesus
Burroughs, Laurence
Woodward, Simon
author_sort Lee, Darren S.
building Nottingham Research Data Repository
collection Online Access
description The reaction of excess TMSCl and LiCCl2Br at low temperature is a technically simple high yield route to TMSCCl2Br. The latter is a stable source of the dichlorobromomethide carbanion, which undergoes 1,4-addition with cyclic nitroalkenes and (E)-fumarates leading to dichlorocyclopropanes after bromide explusion. For nitrostyrenes the reaction arrests at the 1,4-addition product. Low temperature NMR studies and DFT calculations suggest the formation of an ‘ate’ species [(nitronate)SiFMe3]- which, upon boil off of TMSF at 10 - 20 °C, yields the cyclopropane. DFT calculations also support the experimental differences between fluoride and acetate as promotors.
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spelling nottingham-329952020-05-04T17:45:01Z https://eprints.nottingham.ac.uk/32995/ Efficient preparation of TMSCCl2Br and its use in dichlorocyclopropanation of electron deficient alkenes Lee, Darren S. Durán-Peña, Maria Jesus Burroughs, Laurence Woodward, Simon The reaction of excess TMSCl and LiCCl2Br at low temperature is a technically simple high yield route to TMSCCl2Br. The latter is a stable source of the dichlorobromomethide carbanion, which undergoes 1,4-addition with cyclic nitroalkenes and (E)-fumarates leading to dichlorocyclopropanes after bromide explusion. For nitrostyrenes the reaction arrests at the 1,4-addition product. Low temperature NMR studies and DFT calculations suggest the formation of an ‘ate’ species [(nitronate)SiFMe3]- which, upon boil off of TMSF at 10 - 20 °C, yields the cyclopropane. DFT calculations also support the experimental differences between fluoride and acetate as promotors. Wiley-VCH Verlag 2016-04-26 Article PeerReviewed Lee, Darren S., Durán-Peña, Maria Jesus, Burroughs, Laurence and Woodward, Simon (2016) Efficient preparation of TMSCCl2Br and its use in dichlorocyclopropanation of electron deficient alkenes. Chemistry - a European Journal, 2016 (22). ISSN 1521-3765 Dichlorocyclopropane Michael Addition Cyclopropanation Conjugate Addition Cyclopropane http://onlinelibrary.wiley.com/doi/10.1002/chem.201600607/full doi:10.1002/chem.201600607 doi:10.1002/chem.201600607
spellingShingle Dichlorocyclopropane
Michael Addition
Cyclopropanation
Conjugate Addition
Cyclopropane
Lee, Darren S.
Durán-Peña, Maria Jesus
Burroughs, Laurence
Woodward, Simon
Efficient preparation of TMSCCl2Br and its use in dichlorocyclopropanation of electron deficient alkenes
title Efficient preparation of TMSCCl2Br and its use in dichlorocyclopropanation of electron deficient alkenes
title_full Efficient preparation of TMSCCl2Br and its use in dichlorocyclopropanation of electron deficient alkenes
title_fullStr Efficient preparation of TMSCCl2Br and its use in dichlorocyclopropanation of electron deficient alkenes
title_full_unstemmed Efficient preparation of TMSCCl2Br and its use in dichlorocyclopropanation of electron deficient alkenes
title_short Efficient preparation of TMSCCl2Br and its use in dichlorocyclopropanation of electron deficient alkenes
title_sort efficient preparation of tmsccl2br and its use in dichlorocyclopropanation of electron deficient alkenes
topic Dichlorocyclopropane
Michael Addition
Cyclopropanation
Conjugate Addition
Cyclopropane
url https://eprints.nottingham.ac.uk/32995/
https://eprints.nottingham.ac.uk/32995/
https://eprints.nottingham.ac.uk/32995/