Diastereoselectivities in Reductions of α-Alkoxy Ketones Are Not Always Correlated to Chelation-Induced Rate Acceleration

Nicole D. Bartolo, Alana L. Hornstein, Annie Y. Zhao, Keith Woerpel

Research output: Contribution to journalArticle

Abstract

The chelation-control model is used to predict stereochemical outcomes of many organometallic reactions. Diastereoselectivity arises due to reaction with a chelated intermediate with sterically differentiated faces. Earlier studies with dimethylmagnesium established that the chelated intermediate is a minor component of the reaction mixture, so reaction with the chelated intermediate must be faster than reaction with a non-chelated intermediate. High diastereoselectivity and chelation-induced rate acceleration are correlated with some hydride reducing agents. There are examples in which diastereoselectivity is high, but chelation-induced rate acceleration is not observed, however. In other cases, chelation-induced rate acceleration is observed, but diastereoselectivity remains low. These experiments illustrate that a revision to the chelation-control model is needed.

Original languageEnglish (US)
Pages (from-to)296-302
Number of pages7
JournalSynthesis (Germany)
Volume51
Issue number1
DOIs
StatePublished - Jan 1 2019

Fingerprint

Chelation
Ketones
Reducing Agents
Reducing agents
Organometallics
Hydrides
alkoxyl radical
Experiments

Keywords

  • chelation control
  • hydride reductions
  • stereoselectivity

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

Cite this

Diastereoselectivities in Reductions of α-Alkoxy Ketones Are Not Always Correlated to Chelation-Induced Rate Acceleration. / Bartolo, Nicole D.; Hornstein, Alana L.; Zhao, Annie Y.; Woerpel, Keith.

In: Synthesis (Germany), Vol. 51, No. 1, 01.01.2019, p. 296-302.

Research output: Contribution to journalArticle

@article{1d0cdcc2f4744928a856edd8d68b16c2,
title = "Diastereoselectivities in Reductions of α-Alkoxy Ketones Are Not Always Correlated to Chelation-Induced Rate Acceleration",
abstract = "The chelation-control model is used to predict stereochemical outcomes of many organometallic reactions. Diastereoselectivity arises due to reaction with a chelated intermediate with sterically differentiated faces. Earlier studies with dimethylmagnesium established that the chelated intermediate is a minor component of the reaction mixture, so reaction with the chelated intermediate must be faster than reaction with a non-chelated intermediate. High diastereoselectivity and chelation-induced rate acceleration are correlated with some hydride reducing agents. There are examples in which diastereoselectivity is high, but chelation-induced rate acceleration is not observed, however. In other cases, chelation-induced rate acceleration is observed, but diastereoselectivity remains low. These experiments illustrate that a revision to the chelation-control model is needed.",
keywords = "chelation control, hydride reductions, stereoselectivity",
author = "Bartolo, {Nicole D.} and Hornstein, {Alana L.} and Zhao, {Annie Y.} and Keith Woerpel",
year = "2019",
month = "1",
day = "1",
doi = "10.1055/s-0037-1610381",
language = "English (US)",
volume = "51",
pages = "296--302",
journal = "Synthesis",
issn = "0039-7881",
publisher = "Georg Thieme Verlag",
number = "1",

}

TY - JOUR

T1 - Diastereoselectivities in Reductions of α-Alkoxy Ketones Are Not Always Correlated to Chelation-Induced Rate Acceleration

AU - Bartolo, Nicole D.

AU - Hornstein, Alana L.

AU - Zhao, Annie Y.

AU - Woerpel, Keith

PY - 2019/1/1

Y1 - 2019/1/1

N2 - The chelation-control model is used to predict stereochemical outcomes of many organometallic reactions. Diastereoselectivity arises due to reaction with a chelated intermediate with sterically differentiated faces. Earlier studies with dimethylmagnesium established that the chelated intermediate is a minor component of the reaction mixture, so reaction with the chelated intermediate must be faster than reaction with a non-chelated intermediate. High diastereoselectivity and chelation-induced rate acceleration are correlated with some hydride reducing agents. There are examples in which diastereoselectivity is high, but chelation-induced rate acceleration is not observed, however. In other cases, chelation-induced rate acceleration is observed, but diastereoselectivity remains low. These experiments illustrate that a revision to the chelation-control model is needed.

AB - The chelation-control model is used to predict stereochemical outcomes of many organometallic reactions. Diastereoselectivity arises due to reaction with a chelated intermediate with sterically differentiated faces. Earlier studies with dimethylmagnesium established that the chelated intermediate is a minor component of the reaction mixture, so reaction with the chelated intermediate must be faster than reaction with a non-chelated intermediate. High diastereoselectivity and chelation-induced rate acceleration are correlated with some hydride reducing agents. There are examples in which diastereoselectivity is high, but chelation-induced rate acceleration is not observed, however. In other cases, chelation-induced rate acceleration is observed, but diastereoselectivity remains low. These experiments illustrate that a revision to the chelation-control model is needed.

KW - chelation control

KW - hydride reductions

KW - stereoselectivity

UR - http://www.scopus.com/inward/record.url?scp=85058573109&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85058573109&partnerID=8YFLogxK

U2 - 10.1055/s-0037-1610381

DO - 10.1055/s-0037-1610381

M3 - Article

VL - 51

SP - 296

EP - 302

JO - Synthesis

JF - Synthesis

SN - 0039-7881

IS - 1

ER -