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5. Commercial sodium boro hydride was obtained from Ventron Corporation and used directly.
6. Commercial diglyme (dimethyl ether of diethylene glycol) was obtained from Ansul Chemical Company, Marinette, Wisconsin, and purified by distillation from lithium aluminum hydride at 62-63░ (15 mm.)2.
7. (▒)-a-Pinene, b.p. 54░ (22 mm.), was obtained from Aldrich Chemical Company, Inc., and distilled before use.
BORANES IN FUNCTIONALIZATION OF OLEFINS TO AMINES 35
8. Commercial boron trifluoride etherate, b.p. 46░ (10 mm.), available from Matheson Coleman and Bell, was distilled from calcium hydride before use.
9. Caution: Since (▒)-Ó-˛ň´Ô is hydroborated to the dialkyl-borane state (R2BH'), a large amount of hydrogen is evolved on addition of hydroxylamine-O-sulfonic acid. Consequently, the addition should be carried out dropwise and adequate ventilation should be provided.
10. The phosphate salt corresponds to the empirical formula C10H19N-H3PO4.
11. The product showed one peak on gas-phase chromatography (3% SE-30, 70░C).
Hydroxylamine-O-sulfonic acid can also be prepared from hy-droxylamine sulfate and 30% fuming sulfuric acid (oleum).3 The present procedure is essentially that of F. Sommer et al.4
The hydroboration amination sequence in diglyme is a general procedure for the conversion of olefins to primary amines without rearrangement and with predictable stereochemistry.5 An alternative procedure, using tetrahydrofuran as solvent and either hydroxylamine-O-sulfonic acid or chloraminc, is applicable with terminal olefins and relatively unhindered internal and alicyclic olefins.6 O-Mesitylenesulfonylhydroxylamine also gave desired amines in comparable yield.7 Alternative procedures for the hydroboration of olefins use commercially available solutions of di-borane in tetrahydrofuran8 or dimethylsulfide.9
Olefins may be converted to primary amines by the Ritter reaction10 or by reaction with mercuric nitrate in acetonitrile solution.11 In both cases regiospecificity for the formal addition of ammonia across the double bond is opposite to that observed in the hydroboration-amination sequence.
1. Department of Chemistry, Michigan State University, East Lansing, Michigan 44824.
2. G. Zweifel and H. C. Brown, Org. Syn., 52, 59 (1972).
3. H. J. Matsuguma and L. F. Audrieth, Inorg. Syn., 5, 122 (1957).
4. F. Sommer, O. F. Schulz, and M. Nassau, Z. Anorg. A/ig. Chem., 147, 142 (1925)
5. M. W. Rathkc, N. Inouc, K. R. Varma, and H. C. Brown, J. Amer. Chem. Soc., 88,
ORGANIC SYNTHESESŚVOL. 58
6. H. C. Brown, W. R. Heydkemp, E. Breuer, and W. S. Murphy, J. Amer. Chem. Soc., 86, 3565 (1964).
7. Y. Tamura, J. Minamikawa, S. Fujii, and M. Ikeda, Synthesis, 196 (1974).
8. H. C. Brown, ôOrganic Synthesis via Boranesö, John Wiley & Sons, New York, N. Y.
9. C. F. Lane, J. Org. Chem., 39, 1437 (1974).
10. L. I. Krimen and D. J. Cota, Org. React., 17, 213 (1969).
11. H. C. Brown and J. T. Kurek, J. Amer. Chem. Soc., 91, 5647 (1969).
Chemical Abstracts Nomenclature (Collective Index Number; Registry Numbers)
3-Pinanamine (8); (17371-27-6); Bicyclo[3.1.1]heptan-3-amine,
2,6,6-trimethyl- (9); (la,2a,3a,5a)- (35117-66-9); (la,2a,3/3,5a)-(35117-55-6); (la, 20,3a, 5a)- (35117-58-9); (la, 2/3,30,5a)-(35117-61-4)
Hydroxylamine-O-sulfonic acid (8,9); (2950-43-8) Hydroxylamine, sulfate (2:1) (8,9); (10039-54-0)
Chlorosulfonic acid: Chlorosulfuric acid (8,9); (7790-94-5) Sodium borohydride: Borate(l-), tetrahydro-, sodium (8,9); (16940-66-2)
Diglyme: Ether, bis(2-methoxyethyl) (8); Ethane, 1,1 '-oxybis[2-methoxy- (9); (111-96-6)
(▒)-a-Pinene: 2-Pinene (8); Bicyclo[3.1.1]-hept-2-ene, 2,6,6-trimethyl- (9); (80-56-8); (▒) (2437-95-8)
Borane, di-3-pinanyl- (8); Borane, bis(2,6,6-trimethylbicyclo-[3.1.1 ]hept-3-yl)- (9); (1091-56-1)
Lithium aluminum hydride: Aluminate(l-), tetrahydro-, lithium
(8); Aluminate(l-), tetrahydro-, lithium, (T-4)- (9); (16853-85-3) Chloramine: Chloramide (8,9); (10599-90-3)
O-Mesitylenc sulfonylhydroxylamine: Hydroxylamine, O-mesityl-sulfonyl- (8); Hydroxylamine, 0-[(2,4,6-trimethylphenyl)sulfonyl]-
Diborane (4) (8,9); (18099-45-1)
Dimethyl sulfide: Methyl sulfide (8); Methane, thiobis- (9); (75-18-3)
CARBENE GENERATION BY a-ELIMINATION WITH LITHIUM
Submitted by Charles M. Dougherty1 and Roy A. Olofson2 Checked by Mark W. Johnson and Robert M. Coates
Caution\ See benzene warning, p. 168.
A 250-ml., three-necked, round-bottomed flask is equipped with a 50-ml. pressure-equalizing dropping funnel capped by a rubber septum, an efficient reflux condenser connected to a nitrogen inlet, and a magnetic stirrer (Note 1). The flask is charged with 7.02 g. (0.05 mole) of a-chloro-p-xylene (Note 2) and 45.6 g. (0.63 mole) of ethyl vinyl ether (Note 3). A solution of 7.06 g. (0.05 mole) of