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Reduction of 3-Trimethysilylcyclobutanone with KBH4; 3-(Trimethylsilyl)cyclobutanol

SyntheticPage 554
DOI: 10.1039/SP554
Submitted Apr 06, 2012, published Apr 06, 2012
Christopher Kelly (christopher.b.kelly@uconn.edu)
A contribution from Tilley Group


			Reaction Scheme: <IMG src="/images/empty.gif">Reduction of <SPAN id=csm1378725227775 class="csm-chemical-name csm-not-validated" title=3-Trimethysilylcyclobutanone grpid="2">3-Trimethysilylcyclobutanone</SPAN> with KBH<SUB>4</SUB><IMG src="/images/empty.gif">

Chemicals Used

3-Trimethysilylcyclobutanone see 552
KBH(99.9% trace metals basis, Sigma-Aldrich)
2-Propanol (anhydrous, 99.5%)
Deionized Water
Diethyl Ether (CHROMASOLV®, for HPLC, ≥99.9%, inhibitor-free, Sigma-Aldrich)
1 M NaOH soludtion
Brine
Sodium Sulfate (ACS reagent, ≥99.0%, anhydrous, granular, Sigma-Aldrich)   

Procedure

To a 500 mL round bottom flask equipped with stir bar and N2 inlet adaptor was added 12.13 g (0.08542 mol, 1 equiv) of 3-trimethylsilylcyclobutanone was added to a along with 250 mL of a 95:5 2-propanol : water  solution(0.353 M in the cyclobutanone). KBH4 (7.01g, 0.1281 mol, 1.5 molar equiv) was added to the flask via a ground glass funnela,b,c and the solution reaction mixture was placed under a N2 atmosphere. Reaction progress was monitored by GC-MS and, after about 1.5 hr, the reaction was complete.

2-Propanol was removed via rotary evaporation until a cloudy slurry remained. The slurry was diluted with diethyl ether (≈ 200 mL) and was transferred to a 1000 mL separatory funnel. The organic layer was washed with aqueous NaOH (100 mL, 1 M) to remove the boric acid byproduct. The two layers were separated and the aqueous layer was then re-extracted with ether (3X 100 mL). The organic layers were combined and washed with 150 mL brine. The organic layer was dried with Na2SO4 and the volatiles were removed via rotary evaporation under aspirator vacuum in a heated water bath (70oC).  A cloudy oil remained and was further purified by vacuum distillation (bp 80 oC at 30 mm Hg) giving 3-trimethylsilylcyclobutanol as a colorless oil (9.13g,  74.2%).   Ratio of the cis to trans  isomers was determined to be 93:7 by both NMR and GC-MS.2  

Author's Comments

Notes: 

a The solution immediately turned pink upon addition.

bCAUTION: Hydrogen gas was given off in this process.

c After 15 minutes, the reaction returned to its original yellow tinged color.

 

Data

Data is for the major cis isomer  unless otherwise indicated:

1H-NMR
(CDCl3, 300 MHz) δ -0.03 (9H, s),  0.93-1.06 (1H, m), 1.59-1.71 (2H, m), 2.10 (1H, d, OH, J = 7.0 Hz), 2.21-2.32 (2H, m);  trans δ -0.05 (9H, s, Me3Si) – other peaks for the trans isomer were too small to be seen or were obscured by the other isomer

 13C NMR (CDCl3 75 MHz) δ -3.35 (CH3), 11.59 (CH), 35.00 (CH2), 67.11 (CH). trans δ -3.20 (CH3), 11.21 (CH), 34.16 (CH2), 66.90 (CH)

GC-MS (EI) 144 ([M]+, 0.33%), 143 ([M-H]+, 0.59%), 129 ([M-CH3]+, 32.9%) 116 (4.3%), 101 (7.8%), 85 (18.1%), 75 (78.4 %), 73 (100%), 59(15.0%), 54 (24.0%), 45 (24.0%) 43 (20.7%).


Lead Reference

1. S. Kobayashi, H. Miyamura, R. Akiyama, T. Ishida, J. Am. Chem. Soc. 2005, 127, 9251-9254.

Other References

2. X. Creary, E. D. Kochly, J. Org. Chem. 2009, 74, 9044. 

Supplementary Information

1H NMR (cyclobutanol hnmr.jpg)
13C NMR (cyclobutanol c13 nmr.jpg)

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Keywords: alcohols, Alkanes, Borohydride Reduction, Organosilicon Chemistry, reduction, Small Ring Systems

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