Enantioselective NHC-catalysed formal [4+2] cycloaddition of alkylaryl-ketenes with β,γ-unsaturated α-ketophosphonates

Stuart M. Leckie; Charlene Fallan; James E. Taylor; T. Bruce Brown; David Pryde; Tomáš Lébl; Alexandra M.Z. Slawin; Andrew D. Smith

doi:10.1055/s-0033-1338851

Enantioselective NHC-catalysed formal [4+2] cycloaddition of alkylaryl-ketenes with β,γ-unsaturated α-ketophosphonates

Stuart M. Leckie, Charlene Fallan, James E. Taylor, T. Bruce Brown, David Pryde, Tomáš Lébl, Alexandra M.Z. Slawin, Andrew D. Smith

Department of Chemistry

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

14 Citations (SciVal)

Abstract

NHC-mediated enantioselective formal [4+2] cycloadditions of alkylarylketenes with γ-substituted-β,γ-unsaturated α-ketophosphonates is described. A substrate-dependent switch in diastereoselectivity was observed, with γ-aryl α-ketophosphonates providing preferentially the syn-dihydropyranone-phosphonates and γ-methyl α-ketophosphonates favouring the anti-dihydropyranone-phosphonate. In addition, ketene generation in situ retained high levels of stereoselectivity and led to improved product yields when compared with the corresponding two-step procedure.

Original language	English
Article number	ST-2013-R0288-C
Pages (from-to)	1243-1249
Number of pages	7
Journal	Synlett
Volume	24
Issue number	10
Early online date	28 May 2013
DOIs	https://doi.org/10.1055/s-0033-1338851
Publication status	Published - 31 May 2013

Keywords

asymmetric catalysis
asymmetric synthesis
cycloaddition
lactones
N-heterocyclic carbenes

ASJC Scopus subject areas

Organic Chemistry

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10.1055/s-0033-1338851

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title = "Enantioselective NHC-catalysed formal [4+2] cycloaddition of alkylaryl-ketenes with β,γ-unsaturated α-ketophosphonates",

abstract = "NHC-mediated enantioselective formal [4+2] cycloadditions of alkylarylketenes with γ-substituted-β,γ-unsaturated α-ketophosphonates is described. A substrate-dependent switch in diastereoselectivity was observed, with γ-aryl α-ketophosphonates providing preferentially the syn-dihydropyranone-phosphonates and γ-methyl α-ketophosphonates favouring the anti-dihydropyranone-phosphonate. In addition, ketene generation in situ retained high levels of stereoselectivity and led to improved product yields when compared with the corresponding two-step procedure.",

keywords = "asymmetric catalysis, asymmetric synthesis, cycloaddition, lactones, N-heterocyclic carbenes",

author = "Leckie, {Stuart M.} and Charlene Fallan and Taylor, {James E.} and Brown, {T. Bruce} and David Pryde and Tom{\'a}{\v s} L{\'e}bl and Slawin, {Alexandra M.Z.} and Smith, {Andrew D.}",

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doi = "10.1055/s-0033-1338851",

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T1 - Enantioselective NHC-catalysed formal [4+2] cycloaddition of alkylaryl-ketenes with β,γ-unsaturated α-ketophosphonates

AU - Leckie, Stuart M.

AU - Fallan, Charlene

AU - Taylor, James E.

AU - Brown, T. Bruce

AU - Pryde, David

AU - Lébl, Tomáš

AU - Slawin, Alexandra M.Z.

AU - Smith, Andrew D.

PY - 2013/5/31

Y1 - 2013/5/31

N2 - NHC-mediated enantioselective formal [4+2] cycloadditions of alkylarylketenes with γ-substituted-β,γ-unsaturated α-ketophosphonates is described. A substrate-dependent switch in diastereoselectivity was observed, with γ-aryl α-ketophosphonates providing preferentially the syn-dihydropyranone-phosphonates and γ-methyl α-ketophosphonates favouring the anti-dihydropyranone-phosphonate. In addition, ketene generation in situ retained high levels of stereoselectivity and led to improved product yields when compared with the corresponding two-step procedure.

AB - NHC-mediated enantioselective formal [4+2] cycloadditions of alkylarylketenes with γ-substituted-β,γ-unsaturated α-ketophosphonates is described. A substrate-dependent switch in diastereoselectivity was observed, with γ-aryl α-ketophosphonates providing preferentially the syn-dihydropyranone-phosphonates and γ-methyl α-ketophosphonates favouring the anti-dihydropyranone-phosphonate. In addition, ketene generation in situ retained high levels of stereoselectivity and led to improved product yields when compared with the corresponding two-step procedure.

KW - asymmetric catalysis

KW - asymmetric synthesis

KW - cycloaddition

KW - lactones

KW - N-heterocyclic carbenes

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U2 - 10.1055/s-0033-1338851

DO - 10.1055/s-0033-1338851

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JO - Synlett

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ER -

Enantioselective NHC-catalysed formal [4+2] cycloaddition of alkylaryl-ketenes with β,γ-unsaturated α-ketophosphonates

Abstract

Keywords

ASJC Scopus subject areas

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