Remarkable levels of enantioswitching in catalytic asymmetric hydroboration

Sean M. Smith, James M. Takacs

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

TADDOL-derived phosphites and phosphoramidites are effective ligands for rhodium-catalyzed asymmetric hydroborations of β,γ-unsaturated amides, achieving up to 99% ee. However, the sense of stereoinduction, R or S, is surprisingly dependent on rather subtle features of the ligand. For example, catalysts employing a TADDOL phenylphosphite and those using the closely related N-methylaniline-derived phosphoramidite of the same configuration give opposite enantiomers of the product. Those derived from optical antipodes give the same product with virtually the same enantioselectivity as illustrated above. The different stereochemical outcomes may reflect fundamental differences in catalyst structure, reactivity, or reaction mechanism.

Original languageEnglish (US)
Pages (from-to)4612-4615
Number of pages4
JournalOrganic Letters
Volume12
Issue number20
DOIs
StatePublished - Oct 15 2010

Fingerprint

hydroboration
antipodes
Phosphites
Ligands
catalysts
Rhodium
ligands
Catalysts
Enantiomers
Enantioselectivity
enantiomers
products
rhodium
Amides
amides
reactivity
configurations
phosphoramidite
methylaniline

ASJC Scopus subject areas

  • Biochemistry
  • Physical and Theoretical Chemistry
  • Organic Chemistry

Cite this

Remarkable levels of enantioswitching in catalytic asymmetric hydroboration. / Smith, Sean M.; Takacs, James M.

In: Organic Letters, Vol. 12, No. 20, 15.10.2010, p. 4612-4615.

Research output: Contribution to journalArticle

@article{e9d4ff012e2e4cb48ec1d32cd7a028dc,
title = "Remarkable levels of enantioswitching in catalytic asymmetric hydroboration",
abstract = "TADDOL-derived phosphites and phosphoramidites are effective ligands for rhodium-catalyzed asymmetric hydroborations of β,γ-unsaturated amides, achieving up to 99{\%} ee. However, the sense of stereoinduction, R or S, is surprisingly dependent on rather subtle features of the ligand. For example, catalysts employing a TADDOL phenylphosphite and those using the closely related N-methylaniline-derived phosphoramidite of the same configuration give opposite enantiomers of the product. Those derived from optical antipodes give the same product with virtually the same enantioselectivity as illustrated above. The different stereochemical outcomes may reflect fundamental differences in catalyst structure, reactivity, or reaction mechanism.",
author = "Smith, {Sean M.} and Takacs, {James M.}",
year = "2010",
month = "10",
day = "15",
doi = "10.1021/ol101932q",
language = "English (US)",
volume = "12",
pages = "4612--4615",
journal = "Organic Letters",
issn = "1523-7060",
publisher = "American Chemical Society",
number = "20",

}

TY - JOUR

T1 - Remarkable levels of enantioswitching in catalytic asymmetric hydroboration

AU - Smith, Sean M.

AU - Takacs, James M.

PY - 2010/10/15

Y1 - 2010/10/15

N2 - TADDOL-derived phosphites and phosphoramidites are effective ligands for rhodium-catalyzed asymmetric hydroborations of β,γ-unsaturated amides, achieving up to 99% ee. However, the sense of stereoinduction, R or S, is surprisingly dependent on rather subtle features of the ligand. For example, catalysts employing a TADDOL phenylphosphite and those using the closely related N-methylaniline-derived phosphoramidite of the same configuration give opposite enantiomers of the product. Those derived from optical antipodes give the same product with virtually the same enantioselectivity as illustrated above. The different stereochemical outcomes may reflect fundamental differences in catalyst structure, reactivity, or reaction mechanism.

AB - TADDOL-derived phosphites and phosphoramidites are effective ligands for rhodium-catalyzed asymmetric hydroborations of β,γ-unsaturated amides, achieving up to 99% ee. However, the sense of stereoinduction, R or S, is surprisingly dependent on rather subtle features of the ligand. For example, catalysts employing a TADDOL phenylphosphite and those using the closely related N-methylaniline-derived phosphoramidite of the same configuration give opposite enantiomers of the product. Those derived from optical antipodes give the same product with virtually the same enantioselectivity as illustrated above. The different stereochemical outcomes may reflect fundamental differences in catalyst structure, reactivity, or reaction mechanism.

UR - http://www.scopus.com/inward/record.url?scp=77957834351&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=77957834351&partnerID=8YFLogxK

U2 - 10.1021/ol101932q

DO - 10.1021/ol101932q

M3 - Article

C2 - 20863120

AN - SCOPUS:77957834351

VL - 12

SP - 4612

EP - 4615

JO - Organic Letters

JF - Organic Letters

SN - 1523-7060

IS - 20

ER -