[19752-27-3]  · C21H36Sn  · trans-Cinnamyltributylstannane  · (MW 398.15)

(phenylallylating agent as an anion equivalent;1,2 3-carbon component in a [3 + 2] cycloaddition reaction with a,b-unsaturated acylirons3)

Alternate Names: trans-cinnamyltributyltin; trans-(3-phenyl-2-propenyl)tributyltin.

Physical Data: bp 163-166 °C/0.4 mmHg;2 bp 138-142 °C/0.5 mmHg;4 n20D 1.5185.4

Solubility: sol THF, methylene chloride, chloroform.

Preparative Methods: by the coupling reaction of trans-cinnamylmagnesium bromide with Tri-n-butylchlorostannane (10-20%)2,4,5 or trapping of the lithiated derivative of allylbenzene (s-BuLi in cyclohexane/TMEDA/THF) with tributylchlorostannane at -78 °C (90%).6,7

Analysis of Reagent Purity: CH microanalysis; IR (neat)2 2925 (vs), 1637 (s), 1598 (s), 1495 (s), 1463 (s), 1672 (s), 958 (s) cm-1;IR (1% CCl4)4 1635, 956 cm-1; UV (MeOH) lmax 267 nm (log εmax 4.036);4 1H NMR (100 MHz, CCl4) d 0.89 and 1.5 (m, 27H), 1.93 (d, 2H, J = 8 Hz), 5.6-6.4 (m, 2H), 7.09 (m, 5H);2 1H NMR (360 MHz, CDCl3) d 0.80-0.98 (m, 15H), 1.21-1.31 (m, 6H), 1.39-1.57 (m, 6H), 1.95 (dd, 2H, J = 8.7, 1.0 Hz), 6.18 (d, 1H, J = 15.6 Hz), 6.40 (dtd, 1H, J = 15.6, 8.7, 1.0 Hz), 7.0-7.3 (br s, 5H);7,8 13C NMR spectroscopy.

Handling, Storage, and Precautions: although toxicological properties have been virtually unexplored, they may be extrapolated from those observed for Allyltributylstannane.8 Use in a fume hood.

Lewis Acid-Mediated Phenyallylation Reactions.

Phenylallylation reactions can be realized under Lewis-acid catalysis in a similar manner as those observed using allyltributyl- or Allyltriphenylstannane.1 However, the regiochemistry of phenylallyl addition depends upon the nature of the reaction and the structure of the electrophile substrate used. For example, treatment of trans-cinnamyltributyltin with 2,3-dimethylbenzoquinone in the presence of Boron Trifluoride Etherate results in the exclusive allylation at the a-carbon (eq 1).2 In contrast, a similar reaction with 2,6-dimethylbenzoquinone provides a mixture of a- (49%) and g-adducts (32%) at C-3 of the starting benzoquinone.2

trans-Cinnamyltributyltin undergoes a BF3.OEt2-mediated addition reaction with aldehydes (eq 2)7 as other allyltins (see Allyltributylstannane).1 Interestingly, however, the stereochemical outcome of this reaction is opposite to the syn selectivity encountered for the reactions involving Crotyltributylstannane, where the reactions are postulated to proceed through extended transition states.1,9 The observed anti selectivity of the reaction of trans-cinnamyltributyltin has been speculated to proceed through a cyclic transition state, presumably owing to a greater ionic contribution from the C-Sn bond compared with other allyl- or g-alkylallyltins.7

A novel, highly stereoselective [3 + 2] cycloaddition has been developed between allyltins such as trans-cinnamyltributyltin and a,b-unsaturated acyliron complexes (eq 3).3

1. Yamamoto, Y.; Asao, N. CR 1993, 93, 2207.
2. Naruta, Y. JACS 1980, 102, 3774.
3. Herndon, J. W. JACS 1987, 109, 3165. Herndon, J. W.; Wu, C.; Harp, J. J. OM 1990, 9, 3157.
4. Roberts, R. M. G.; El Kaissi, F. JOM 1968, 12, 79.
5. Tanigawa, Y.; Moritani, I.; Nishida, S. JOM 1971, 28, 73.
6. Heiszwolf, G. J.; Kloosterziel, H. RTC 1967, 86, 1345. Sandel, V. R.; McKinley, S. V.; Freedman, H. H. JACS 1968, 90, 495.
7. Koreeda, M.; Tanaka, Y. CL 1982, 1299. See also: Coxson, J. M.; van Eyk, S. J.; Steel, P. J. TL 1985, 26, 6121. Uneyama, K.; Nanbu, H.; Torii, S. TL 1986, 27, 2395.
8. For the toxicological properties of Allyltributylstannane, see: Lenga, R. E. Sigma-Aldrich Library of Chemical Safety Data, 2nd ed.; Aldrich: Milwaukee, 1987; Vol. 2, p 168C.
9. Yamamoto, Y.; Yatagai, H.; Naruta, Y.; Maruyama, K. JACS 1980, 102, 7107.

Masato Koreeda

The University of Michigan, Ann Arbor, MI, USA

Copyright 1995-2000 by John Wiley & Sons, Ltd. All rights reserved.