RCHO ---> RCH3


RCOOR' ---> RCH3(+R'OH)


R	R"	R      R"
 \     /         \    /
  C - C   --->    CH-CH
 / \ / \         /    \
R'  0   H	R'     H

saturated hydrocarbons with preservation of the carbon skeleton,⁴ reductions occurring in good yield at room temperature.
Although this type change can be realized through the Wolff-Kishner (basic) or Clemmensen (acidic) reaction on aldehydes, the corresponding transformations with esters and l,2-oxides ⁵ are, as far as we know, not precedented.

The procedure is illustrated with dodecanal, the carbonyl compound selected for various studies on the aldehyde reaction. In a glove box or Schlenk apparatus rigorously free of oxygen,⁶ 2.5 g (10 mmol) of recrystallized (CHCl₃) titanocene dichloride, 0.5 g (22 mmol) of fine sodium sand, 12 ml of dry, deoxygenated benzene (purified by distillation from sodium benzophenone ketyl), and a 1-in. Teflon stirring bar were added to a 50-m1 round-bottomed flask. The mixture was stirred at the highest possible speed until the supernate turned a dark green (10-48 hr) and then was immediately filtered with benzene washing through a glass frit, thereby being freed from NaCl, unreacted sodium, and insoluble polymeric titanium species (CAUTION: the gray-black residue warms up and can ignite upon exposure to air). To the dark greenish filtrate⁷ was added 36.8 mg (0.2 mmol) of dodecanal. After being stirred 72 hr, 5 ml of degassed water was added to the mixture while maintaining inert atmosphere conditions; over the course of 4-8 hr, the reaction mixture turned a dark purple. The benzene was removed under reduced pressure, and the product was extracted with petroleum ether. Drying, concentration, and silica gel chromatography yielded 24.1 mg of pure dodecane (71 %), characterized by gas chromatography (gc) and mass spectrometry. About 15-20% dodecanol was formed concurrently.

In experiments with molar ratios of starting titanocene dichloride-dodecanal less than 10:1, much less total product is recoverable. At temperatures either lower or higher than ambient, considerably more alcohol and much less alkane are generated.
By means of the outlined procedure, decanal and 2-methylundecanal were converted in similar yield to decane and 2-methylundecane, respectively. Ketones afforded much less hydrocarbon (7-25 %) and correspondingly larger amounts of alcohol (up to 74 %) and starting materials (Table I).

When subjected to the above conditions, many esters are reduced to hydrocarbons in acceptable yields (see Table I). Although in poorer yields, dodecanoyl chloride (18-45%), dodecanoic acid (2 %), and lithium dodecanoate (25 %) were transformed to dodecane.
1,2-Oxides are reduced to alkanes (Table I) under the same conditions used for aldehydes and esters. Also, as single case examples, nonane (27 %) and dodecane (98%) were formed respectively from nonyl isocyanide and dodecyl bromide. Dodecane is produced from both dodecyl mercaptan (20%) and didodecyl sulfide (11-13 %). Only starting material was recovered when reduction was attempted with alcohols, alkoxides, or acyclic ethers.
That the reagent employed in the described reactions

Table I. Reduction of Carbonyl Compounds and 1,2-Oxides:

Starting material	Product	% Yields
- Aldehydes & Ketones -
Dodecanal	Dodecane	71 b
	Dodecanol	15-20
Decanal	Decane	61
	Decanol	11
2-Methylundecanal	2-Methylundecane	44
trans-2-Decanal	Decane	0-22
	1-Decene	0 (zero)
	Decanol	0-5
p-Methoxybenzaldehyde	p-Cresol methyl ether	0 (zero)
2-Undecanone	Undecane	3-20
	2-Undecanal	48-72
6-Dodecanone	Dodecane	7-25
	6-Dodecanol	32-70
2-Adamantanone	2-Adamantanol	72-74
- Esters -
Methyl dodecanoate	Dodecane	66
	Dodecanol	9
Ethyl dodecanoate	Dodecane	64-69
	trans-2-Dodecene	0-4
	Dodecanol	9-14
Decyl dodecanoate	Dodecane	58
	trans-2-Dodecene	2
	Dodecanol	7
	Decanol	70
Methyl trans-2-decenoate	Decane	3-35
	1-Decene	0 (zero)
	Decanol	0-2
gamma-Decalactone	4-Decanol	60
Methyl trans-myrtanoate	trans-Pinane	17
	trans-Myrtanol	28
Methyl 1-adamantane-carboxylate	1-Methyladamantane	0 (zero)
	Adamantylcarbinol	35-64
Methyl 5 Beta-cholanate	5 Beta-Cholane	56 b
Methyl p-isopropylbenzoate	p-Isopropyl benzyl alcohol	82
- Oxides -
1-Decene oxide	Decane	68-81
	1-Decanol	4-9
trans-2-Decene oxide	Decane	58
2-Methyl-1-undecene oxide	2-Methylundecane	52
alpha-Pinene oxide	cis-Pinane	10

^a Product identity and yields were determined by gc and mass spectral methods.
^b Yields also based on isolated product.

is extraordinary is revealed by reduction attempts with other transition metal species. No dodecane (or dodecene) was formed from dodecanal when the following systems were assayed: (C₅H₅)₂MoH₂,
(C5H5)2MoH2-isoprene,8 TiH2, VH, Na, VCl2_3-Na,
MoCl_3-4,-Na. A few per cent of alkane was detected after reaction with (C₅H₅)₂MoH₂ with a catalytic amount of HCl, (C₅H₅)₂TaH₃ (80°),⁹ or Fe(acac)3Na.
Various observations signify that the reduction of aldehydes and esters to alkanes involves olefin intermediates. Interruption of a dodecanal reaction after 3 hr revealed 10-15% 1- and 2-dodecene with 37-44% dodecane. As reaction time increased, the yield of dodecane became optimal while the amount of olefin approached zero. Olefin reduction during the overall reaction is consistent with the separate conversion of ldecene by the usual titanocene preparation to decane in 76-89% yield. When a dodecanal reduction was carried out starting with (C₅H₅)(C₅D₅)TiCl₂, highly deuterated decane (d₁-d₁₆) was formed (as evidenced by gc and mass spectral data), thereby revealing extensive exchange of titanocene deuterium, presumably with hydrogen of intermediate olefin. Further, when an aliquot removed after 3 hr from a dodecanal reaction was quenched with D₂O, ca. 50% of the dodecane contained two deuteriums (mass spectral), while remaining alkane and 1-dodecene possessed deuterium at ca. natural abundance levels. However, reactions quenched with D20 after 72 hr featured substantially less deuterium incorporation. No deuterium was transferred to hydrocarbon product from benzene-d6 solvent. The foregoing results indicate the formation of intermediate titanium-bound olefin, which can be converted to alkane by D₂0-H₂0 or by hydride from cyclopentadienide ligands. Similar deuterium labeling results were secured with ethyl dodecanoate, thus sug-

RR'CHCOOR" ---> RR'CHCHO --> 
RR'C=CH2 + [(C5H5)2Ti]n	RR'C=CH2 • [(C5H5)2Ti]n --> RR'CHCH3,

gesting that with esters initial reduction to the aldehyde level is followed by steps identical with those involved in reductions starting with aldehydes. In keeping with the suggested scheme, no hydrocarbon was formed from aldehydes and esters which would not be expected to form olefins, including aromatic aldehydes and ladamantane carboxylic acid methyl ester. Although the driving force for the conversion of aldehyde to olefin must be formation of the titanium-oxygen bond by a reactive titanocene species, the exact mechanism of deoxygenation has not been established. That epoxide deoxygenation conforms to the pattern is revealed through D20 quenching of the 1-decene oxide reaction after 3 hr, whereupon 1-decene, 2-decene, and decane emerged with deuterium levels at or slightly above natural abundance.

Acknowledgment.
Financial support was provided by NIH Grant GMl3797.

E. E. van Tamelen,* J. A. Gladysz

Department of Chemistry, Stanford University

Stanford, California 94305

Received May 11, 1974



Refs:
(1) E. E. van Tamelen, R. B. Fechter, S. W. Schneller, G. Boche, R. H. Greeley, and B. Akermark, J. Amer. Chem. Soc., 91, 1551 (1969); (b) E. E. van Tamelen, D. Seeley, S. Schneller, H. Rudler, and W. Cretney, ibid., 92, 5151 (1970); (c) J. E. Bercaw, R. H. Narvich, L. G. Bell, and H. H. Brintinger, ibid., 94, 1219 (1972).
(2) E. E. van Tamelen, W. Cretney, N. Klaentschi, and J. S. Miller, J. Chem. Soc., Chem. Commun., 481 (1972).
(3) E. E. van Tamelen, H. Rudler, and C. Bjorklund, J. Amer. Chem. Soc., 93, 7113 (1971).
(4) For the preparation of alkanes through aldehyde or acyl chloride decarbonylation, see J. Tsuji and K. Ihno, Synthesis, 1, 157 (1969).
(5) For two-electron reductions of epoxides to alkenes, see K. B. Sharpless, M. A. Umbreit, M. T. Nieh, and T. C, Flood, J. Amer. Chem. Soc., 94, 6538 (1972), and references cited therein.
(6) Catalytic amounts of oxygen inhibit this reaction and for obvious reasons, nitrogen must also be excluded.
(7) A brown color indicates incomplete reduction and a yellow color reflects oxygen contamination of the reaction mixture, which then should not be used.
(8) These conditions are believed to produce a molybdenocene intermediate: B. R, Francis, M. L. H. Green, and G. G. Roberts, Chem. Commun., 1290 (1971); M. L. H. Green and P. J. Knowles, J. Chem. Soc. A, 1508 (1971).
(9) In refluxing benzene, (C6H5)2TaH3, evolves H2 to give an intermediate isoelectronic with titanocene: E, K. Barefield, G. W. Parshall, and F. N. Tebbe, J. Amer. Chem. Soc., 92, 5235 (1970).