[84531-04-4]  · C4H5Li  · 1,3-Butadienyl-2-lithium  · (MW 60.02)

(reagent for carbon-carbon bond forming reactions with carbonyls1,2 and a,b-alkenyl esters3,4)

Preparative Methods: 1,3-butadienyl-2-lithium is synthesized by transmetalation of 1,2-butadienyl-2-tributyltin (eq 1)1 or by the Shapiro reaction of 2,4,6-(i-Pr)3C6H2SO2NHN=CMeCH=CH2 with Methyllithium (eq 2).2 3-Methyl-1,3-butadienyl-2-lithium has been prepared by lithium-bromine exchange.5.

Analysis of Reagent Purity: 1,3-butadienyl-2-lithium is synthesized and used direclty without further isolation or purification.

Handling, Storage, and Precautions: use in a fume hood.

Reaction with Aldehydes and Ketones.

1,3-Butadienyl-2-lithium reacts with aldehydes and ketones. Dienyl carbinols are generally obtained as major products, along with small amounts of allenyl carbinols (eq 3). Compared with 1,3-Butadienyl-2-magnesium Chloride, a stronger preference for dienyl products is observed (Table 1).1

1,3-Butadienyl-2-lithium undergoes Michael addition to a,b-alkenyl esters. The reaction with methyl 2-(trimethylsilyl)propenoate affords the corresponding lithium enolate, which upon alkylation yields a series of a-silyl esters (eq 4).3

Treatment of the Michael adduct with an aldehyde followed by Peterson alkenation furnishes the dienyl a,b-alkenyl ester (eq 5).4 Stereoselectivities of the products vary with the substrate (E/Z = ca. 3:1 to Z only).4

Substituted 2-lithiobutadienes which have been prepared include 3-methyl-,5 3-trimethylstannyl-,6 3-trimethylsilyl-,6 3-hexyl-,6 and 4-methoxy-1,3-butadienes.7

Related Reagents.

1,3-Butadienyl-1-lithium; 1,3-Butadienyl-1-magnesium Chloride; 1,3-Butadienyl-2-magnesium Chloride.

1. Wada, E.; Kanemasa, S.; Fujiwara, I.; Tsuge, O. BCJ 1985, 58, 1942.
2. (a) Brown, P. A.; Jenkins, P. R. TL 1982, 23, 3733. (b) JCS(P1) 1986, 1129.
3. Tanaka, J.; Kanemasa, S.; Ninomiya, Y.; Tsuge, O. BCJ 1990, 63, 476.
4. (a) Tsuge, O.; Kanemasa, S.; Ninomiya, Y. CL 1984, 1993. (b) Tanaka, J.; Kanemasa, S.; Ninomiya, Y.; Tsug, O. BCJ 1990, 63, 466.
5. Shea, K. J.; Sakata, S. T. TL 1992, 33, 4261.
6. Reich, H. J.; Reich, I. L.; Yelm, K. E.; Holladay, J. E.; Gschneidner, D. JACS 1993, 115, 6625.
7. Schreiber, S. L.; Kiessling, L. L. JACS 1988, 110, 631.

Yusuke Kawakami & Atsunori Mori

Japan Advanced Institute of Science & Technology, Ishikawa, Japan

Sadaaki Nunomoto

Toyama National College of Technology, Japan

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