Synthesis of 1,2,3,4,5,6-Hexahydrophosphinine 1-Oxides by Catalytic Hydrogenation of 3-Phosphabicyclo[3.1.0]hexane 3-Oxides
1
Department of Organic Chemical Technology, Technical University of Budapest, 1521 Budapest, Hungary
2
EGIS Pharmaceuticals, 1475 Budapest, Hungary
*
Author to whom correspondence should be addressed.
Molecules 1997, 2(2), 43-45; https://doi.org/10.3390/feb97p3
Submission received: 20 October 1996
/
Accepted: 25 October 1996
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Published: 25 February 1997
Abstract
:Synthesis of 1,2,3,4,5,6-hexahydrophosphinine 1-oxides by catalytic hydrogenation of 3- phosphabicyclo[3.1.0]hexane 3-oxides was reported in this communication.
6,6-Dichloro-3-phosphabicyclo[3.1.0]hexanes (1) easily available from 3-phospholene 1-oxides by the addition of dichlorocarbene to the double bond [1,2] are useful intermediates for the preparation of 1,2,3,4,5,6-hexahydrophosphinine 1-oxides (3). In the first method, the dichlorocarbene adducts (1) were transformed to the isomeric mixtures (A) and (B) of the dihydrophosphinine oxides (2) by thermolysis [2], that were then hydrogenated catalytically to give hexahydrophosphinine oxides (3) [3] (Scheme 1).
It was also possible to convert the dichlorocarbene adducts (1) to the hexahydrophosphinines (3) in one pot: catalytic hydrogenation of starting materials 1 till the absorption of three equivalents of hydrogen afforded products 3 [4] (Scheme 1).
As can be seen from Table 1, yields of the p-alkoxy hexahydrophosphinine oxides (3c-e) are better by the onepot method (60-78%), than those by the two-step conversion (25-40%).
Table 1.
Yields of hexahydrophosphinine oxides 3a-e by the two methods (Scheme 1).
| Y | 1→2→3 | 1→4→5→3 |
|---|---|---|
| Yield (%) | ||
| Ph (a) | - | 70 |
| n-Bu (b) | - | 58 |
| EtO (c) | 25 | 73 |
| n-PrO (d) | 28 | 60 |
| i-PrO (e) | 40 | 78 |
Scheme 3.
Carrying out the hydrogenations in the presence of three equivalents of diethylamine, it was possible to stop the transformations at an intermediate stage. Such a mixture contained 40-64% of the two isomers (isomer1 and isomer2) of the monochlorocyclopropanes (4a and 4e) and 36-40% of the corresponding hexahydrophosphinine oxide (3a and 3e) (Scheme 2). Isomers 41 and 42 could be distinguished on the basis of the different 3JHH values of the two H-C5-C6-H moieties. In the case of the P-phenyl model, the fully dechlorinated derivative (6) could also be isolated in 20% yield.
Reduction of the dichlorocarbene adduct 1a with LiAlH4 resulted in the formation of partially and fully dehalogenated phosphines 7 and 8, that gave phosphine oxides 4 and 6 after oxidation (Scheme 3).
Acknowledgement
The authors thank the OTKA support of this work (Grant No. T 014917).
References
- Keglevich, Gy.; Petneházy, I.; Miklós, P.; Almásy, A.; Tóth, G.; Tôke, L.; Quin, L. D. J. Org. Chem. 1987, 52, 3983. [CrossRef]
- Keglevich, Gy.; Brlik, J.; Janke, F.; Tôke, L. Heteroatom Chem. 1990, 1, 419.
- Keglevich, Gy.; Kovács, A.; Újszászy, K.; Tungler, A.; Tóth, G.; Tôke, L. Phosphorus Sulfur 1992, 70, 219.
- Keglevich, Gy.; Tungler, A.; Novák, T.; Tôke, L. J. Chem. Res. (S) 1996, 528.
- Sample Availability: Supporting sample 3a, MDPI 4683, is available from MDPI.
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MDPI and ACS Style
Keglevich, G.; Tungler, A.; Újszászy, K.; Novák, T.; Tôke, L. Synthesis of 1,2,3,4,5,6-Hexahydrophosphinine 1-Oxides by Catalytic Hydrogenation of 3-Phosphabicyclo[3.1.0]hexane 3-Oxides. Molecules 1997, 2, 43-45. https://doi.org/10.3390/feb97p3
AMA Style
Keglevich G, Tungler A, Újszászy K, Novák T, Tôke L. Synthesis of 1,2,3,4,5,6-Hexahydrophosphinine 1-Oxides by Catalytic Hydrogenation of 3-Phosphabicyclo[3.1.0]hexane 3-Oxides. Molecules. 1997; 2(2):43-45. https://doi.org/10.3390/feb97p3
Chicago/Turabian StyleKeglevich, György, Antal Tungler, Kálmán Újszászy, Tibor Novák, and László Tôke. 1997. "Synthesis of 1,2,3,4,5,6-Hexahydrophosphinine 1-Oxides by Catalytic Hydrogenation of 3-Phosphabicyclo[3.1.0]hexane 3-Oxides" Molecules 2, no. 2: 43-45. https://doi.org/10.3390/feb97p3
