Acceptorless dehydrogenative coupling of primary alcohols to esters by heterogeneous Pt catalysts

Catal. Sci. Technol., 2014, 4,3631-3635
DOI: 10.1039/C4CY00979G, Communication

Sondomoyee Konika Moromi, S. M. A. Hakim Siddiki, Md. Ayub Ali, Kenichi Kon, Ken-ichi Shimizu
Pt/SnO₂ is presented as the first example of a reusable heterogeneous catalyst for acceptorless dehydrogenative coupling of primary alcohols to esters under additive-free and solvent-free conditions.



 Supported platinum catalysts have been studied for the acceptor-free dehydrogenative 
coupling of primary alcohols to esters in the liquid phase under solvent-free conditions in N₂ at 180 °C. 
The activity depends on the support material, and Pt-loaded SnO₂ (Pt/SnO₂) gives the highest activity. Pt/SnO₂ shows higher activity than various transition metals
 (Ir, Re, Ru, Rh, Pd, Ag, Co, Ni, Cu) loaded on SnO₂. The Pt/SnO₂  
catalyst (1 mol%) selectively converted various primary alcohols to their corresponding esters in moderate to 
high isolated yield (53–91%). This is the first example of reusable heterogeneous catalysts for the acceptor-free dehydrogenative coupling of primary alcohols to esters 
under additive-free and solvent-free conditions. Mechanistic and infrared
 (IR) studies are also shown to discuss the reaction pathway and a possible role of the SnO₂ support as Lewis acid sites that activate carbonyl groups of adsorbed aldehyde intermediates.

Acceptorless dehydrogenative coupling of primary alcohols to esters by heterogeneous Pt catalysts

Sondomoyee Konika Moromi,^a   S. M. A. Hakim Siddiki,^b  Md. Ayub Ali,^a   Kenichi Kon^a and   Ken-ichi Shimizu*^ab  

*

Corresponding authors

^a

Catalysis Research Center, Hokkaido University, N-21, W-10, Sapporo 001-0021, Japan 
E-mail: kshimizu@cat.hokudai.ac.jp;
Fax: +81 11 706 9163

^b

Elements Strategy Initiative for Catalysts and Batteries, Kyoto University, Katsura, Kyoto 615-8520, Japan

Catal. Sci. Technol., 2014,4, 3631-3635

DOI: 10.1039/C4CY00979G

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A Catalyst That Multitasks To Make Complex Molecules Organic Synthesis: Method leads to complex, biologically relevant molecules on gram scale

A copper catalyst guides this multicomponent reaction. 

A new synthetic strategy that relies on a multitasking copper catalyst allows chemists to construct useful molecules faster and with higher yield. Experts say it promises to fast-track complicated syntheses.

Fewer steps in a chemical synthesis often translate to a better yield of the final product. Chemists therefore prize so-called multicomponent reactions that orchestrate the assembly of multiple building blocks into a complex structure in a single stroke.

Boston College chemists Amir H. Hoveyda, Fanke Meng, and Kevin P. McGrath demonstrate their virtuosity in this regard by using an inexpensive copper catalyst that puts together complex molecules from an allene, a diboron reagent, and an allylic phosphate. The resulting products contain a stereogenic carbon center, a monosubstituted alkene, and a tough-to-synthesize Z-trisubstituted alkenylboron (Nature 2014, DOI: 10.1038/nature13735).

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http://cen.acs.org/articles/92/i38/Catalyst-Multitasks-Make-Complex-Molecules.html

Metal-free coupling of saturated heterocyclic sulfonylhydrazones with boronic acids

Metal-free coupling of saturated heterocyclic sulfonylhydrazones with boronic acids 

Daniel M. Allwood *†, David C. Blakemore ‡, Alan D. Brown ‡, and Steven V. Ley †

† Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, U.K.

‡ Neusentis Chemistry, Pfizer Worldwide Research and Development, The Portway Building, Granta Park, Cambridge, CB21 6GS, U.K.

J. Org. Chem., 2014, 79 (1), pp 328–338

DOI: 10.1021/jo402526z

http://pubs.acs.org/doi/abs/10.1021/jo402526z

The coupling of aromatic moieties with saturated heterocyclic partners is currently an area of significant interest for the pharmaceutical industry. Herein, we present a procedure for the metal-free coupling of 4-, 5-, and 6-membered saturated heterocyclic p-methoxyphenyl (PMP) sulfonylhydrazones with aryl and heteroaromatic boronic acids. This procedure enables a simple, two-step synthesis of a range of functionalized sp2–sp3 linked bicyclic building blocks, including oxetanes, piperidines, and azetidines, from their parent ketones.

Flow chemistry syntheses of natural products

 Flow chemistry syntheses of natural products ..click here

J.C. Pastre, D.L. Browne, S.V. Ley, Chem. Soc. Rev. 2013, 42, 8801-9198.

The development and application of continuous flow chemistry methods for synthesis is a rapidly growing area of research. In particular, natural products provide demanding challenges to this developing technology. This review highlights successes in the area with an emphasis on new opportunities and technological advances.

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http://pubs.rsc.org/en/Content/ArticleLanding/2013/CS/c3cs60246j#!divAbstract

Benzocoumarin Family Complete

Benzocoumarin Family Complete

Benzo[g]coumarins most suitable for applications as photonic materials
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 Benzene-fused coumarins, benzocoumarins, constitute a promising family of photonic materials due to the extended nature of their π-electron system. Among four possible subfamilies of benzocoumarins



 http://www.chemistryviews.org/details/ezine/6508251/Benzocoumarin_Family_Complete.html

Bispirooxindole Derivatives

Bispirooxindole Derivatives

Regio- and stereoselective synthesis of bispirooxindole derivatives via a three-component 1,3-dipolar cycloaddition
Read more

An efficient synthesis of spirooxindole derivatives is highly valued due to the pronounced biological activities of this class of compounds.

http://www.chemistryviews.org/details/ezine/6522871/Bispirooxindole_Derivatives.html

7,7-dichlorobicyclo[4.1.0]heptane (7,7-dichloronorcarane

7,7-dichlorobicyclo[4.1.0]heptane (7,7-dichloronorcarane

+

NaOH,Pr3N

+

Synthesis of 7,7-dichlorobicyclo[4.1.0]heptane (7,7-dichloronorcarane) from cyclohexene

Reaction type:	addition to alkenes, elimination, cycloaddition
Substance classes:	alkene, carbene, chloroalkane
Techniques:	stirring with magnetic stir bar, adding dropwise with an addition funnel, distilling under reduced pressure, evaporating with rotary evaporator, shaking out, extracting, filtering, use of an ice cooling bath, heating with oil bath

http://kriemhild.uft.uni-bremen.de/nop/en/instructions/pdf/3005_en.pdf

Instruction (batch scale 100 mmol)
Equipment
100 mL three neck round bottom flask, reflux condenser, addition funnel with pressure
balance, heatable magnetic stirrer, magnetic stir bar, thermometer for inside of the flask,
separating funnel, destillation apparatus, rotary evaporator, oil bath, ice bath, vacuum pump
Substances
cyclohexene (bp 83 °C) 8.21 g (10.1 mL, 100 mmol)
chloroform (bp 61 °C) 48.0 g (32.7 mL, 400 mmol)
sodium hydroxide 16.0 g (400 mmol)
tri-n-propylamine (bp 156 °C) 0.14 g (0.19 mL, 1.0 mmol)
water 16 mL
ethanol (bp 78 °C) 1 mL
n-pentane (bp 36 °C) 120 mL
sodium sulfate for drying about 5 g
sodium chloride about 18 g
Reaction
Into a 100 mL three neck round bottom flask equipped with a reflux condenser addition
funnel, thermometer for measuring the inside temperature and magnetic stir bar, 8.21 g
(10.1 mL, 100 mmol) cyclohexene 0.14 g (0.19 mL, 1.0 mmol) tri-n-propylamine, 48.0 g
(32.7 mL, 400 mmol) chloroform and 1 mL ethanol is added. The mixture is cooled to 0 °C
with an ice bath, then under stirring and further cooling in the ice bath a solution of 16.0 g
(400 mmol) sodium hydroxide in 16 mL water is added through an addition funnel. The
mixture should be stirred vigourously during the next 20 minutes at 0 °C. After this time the
mixture is further stirred during 1 hour at room temperature and 3 hours at 50 °C.
Work up
Chloroform is evaporated with a rotary evaporator, then the residue is transferred with about
50 mL water and 30 mL n-pentane into a separating funnel. The organic phase is separated,
the aqueous phase is further extracted three times with 30 mL pentane. If an emulsion is
formed the aqueous phase is saturated with NaCl. The combined organic phases are dried over
sodium sulfate. The solution is filtered from sodium sulfate and the solvent is evaporated with
a rotary evaporator, yielding a nearly colourless liquid as crude product. The crude yield is
14.6 g. The crude product is distilled under reduced pressure.
Yield: 13.6 g (82.3 mmol, 82%), colourless liquid; bp 77 °C (11 hPa)

Operating scheme

Operating scheme

Equipment

Batch scale:

0.01 mol

0.1 mol

1 mol

Cyclohexene

	two-necked flask 10 mL			reflux condenser
	heatable magnetic stirrer with magnetic stir bar			thermometer
	graduated pipette			separating funnel
	microdistillation apparatus			rotary evaporator
	oil bath			ice bath
	vacuum pump

................ 




GC: pure productcolumnSE-54, L= 25 m, ID 0.32 mm, DF 0.25 µm (Macherey & Nagel)inletGerstel KAS, injector: 250°C, split injection 1:20, 0.15 µLcarrier gasN2, pre-column pressure 62 kPa, 1.04 mL/minoven80 °C (1 min), 10 °C/min --> 250 °C (30 min)detectorFID, 275 °Cintegrationpercent concentration calculated from relative peak area

1H-NMR: 7,7-Dichlorobicyclo[4.1.0]heptane
500 MHz, CDCl3
delta [ppm]	mult.	atoms	assignment
1.12-1.36	m	4 H	C4-H, C5-H
1.61-1.71	m	4 H	C3-H, C6-H
1.88-1.98	m	2 H	C1-H, C2-H
7.26	s	1 H	CHCl3

3C-NMR: 7,7-Dichlorobicyclo[4.1.0]heptane
125 MHz, CDCl3
delta [ppm]	assignment
18.9	C4, C5
20.2	C3, C6
25.8	C2, C1
67.4	C7
76.5-77.5	CDCl3

IR: 7,7-Dichlorobicyclo[4.1.0]heptane
[Film, T%, cm-1]
[cm-1]	assignment
2944, 2855	aliph. C-H valence
796	C-Cl valence

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