In(III)/PhCO2H binary acid catalyzed tandem [2 + 2] cycloaddition and Nazarov reaction between alkynes and acetals.

In(III)/PhCO2H binary acid catalyzed tandem [2 + 2] cycloaddition and Nazarov reaction between alkynes and acetals.

Organic letters (2013-08-21)

Lihui Zhu, Zhi-Guo Xi, Jian Lv, Sanzhong Luo

ABSTRACT

A facile tandem [2 + 2] cycloaddition and Nazarov reaction has been developed. The combination of In(OTf)3 and benzoic acid was found to synergistically promote the coupling of alkynes and acetals to form 2,3-disubstituted indanones in excellent yield and diastereoselectivity.

MATERIALS

Product Number

Brand

Product Description

06185

Supelco

Benzoic acid, Standard for quantitative NMR, TraceCERT^®, Manufactured by: Sigma-Aldrich Production GmbH, Switzerland

PHR1050

Supelco

Benzoic acid, Pharmaceutical Secondary Standard; Certified Reference Material

76170

Supelco

Melting point standard 121-123°C, analytical standard

03-1150

Sigma-Aldrich

Benzoic acid, SAJ first grade, ≥99.5%

33047

Sigma-Aldrich

Benzoic acid, puriss. p.a., ACS reagent, reag. Ph. Eur., ≥99.9% (alkalimetric)

18102

Sigma-Aldrich

Benzoic acid, meets analytical specification of Ph. Eur., BP, USP, FCC, E210, 99.5-100.5% (alkalimetric)

12353

Supelco

Benzoic acid, reference material for titrimetry, certified by BAM, >99.5%

85325

Sigma-Aldrich

Silver trifluoromethanesulfonate, purum, ≥98.0% (Ag)

109479

Sigma-Aldrich

Benzoic acid, ReagentPlus^®, 99%

W213101

Sigma-Aldrich

Benzoic acid, ≥99.5%, FCC, FG

W213128

Sigma-Aldrich

Benzoic acid, natural, ≥99.5%, FCC, FG

427608

Sigma-Aldrich

Benzoic acid, purified by sublimation, ≥99%

483346

Sigma-Aldrich

Silver trifluoromethanesulfonate, ≥99.95% trace metals basis

242381

Sigma-Aldrich

Benzoic acid, ACS reagent, ≥99.5%

515884

Sigma-Aldrich

Aluminum trifluoromethanesulfonate, 99.9% trace metals basis

176435

Sigma-Aldrich

Silver trifluoromethanesulfonate, ≥99%

290009

Sigma-Aldrich

Potassium benzoate, ReagentPlus^®, 99%

03-1140

Sigma-Aldrich

Benzoic acid, SAJ special grade, ≥99.5%

282669

Sigma-Aldrich

Lithium trifluoromethanesulfonate, 96%

430609

Sigma-Aldrich

Lanthanum(III) trifluoromethanesulfonate, 99.999% trace metals basis

290068

Sigma-Aldrich

Zinc trifluoromethanesulfonate, 98%

347817

Sigma-Aldrich

Trifluoromethanesulfonic acid, ReagentPlus^®, ≥99%

481548

Sigma-Aldrich

Lithium trifluoromethanesulfonate, 99.995% trace metals basis

158534

Sigma-Aldrich

Trifluoromethanesulfonic acid, reagent grade, 98%

73983

Supelco

Mettler-Toledo Calibration substance ME 18555, Benzoic acid, analytical standard, (for the calibration of the melting point system), traceable to primary standards (LGC)