Synthesis of Symmetrical Polyenes by Allylzincation

Abstract

Allylzinc bromide reacts with lithium chloroacetylenide to give 4-allyl-4-methylhepta-1,6-diene in good yield. The reaction of allylzinc bromide with acetylene, prop-1-ynylmagnesium bromide and 3-bromoprop-1-yne resulted in the synthesis of 4-­methylhepta-1,6-diene, 4,4-dimethylhepta-1,6-diene and 1,1-diallylcyclopropane respectively. These symmetrical polyenes were oxidized by MCPBA to yield the corresponding epoxides (the molar ratio of the reactants determined which epoxide formed).

Key words

allylzinc bromide - alkynes - diastereoselectivity - unconjugated polyenes - epoxidations

References

• 1 Gaudemar M. C. R. Acad. Sci., Ser. C  1971,  273:  1669 
• 2 Frangin Y. Gaudemar M. C. R. Acad. Sci., Ser. C  1974,  278:  885 
• 3 Frangin Y. Gaudemar M. Bull. Soc. Chim. Fr.  1976,  1173 
• 4 Bellassoued M. Frangin Y. Gaudemar M. Synthesis  1977,  205 
• 5 Negishi E.-i. Miller JA. J. Am. Chem. Soc.  1983,  105:  6761 
• 6 Knochel P. In Comprehensive Organic Synthesis   Vol. 4-5:  Trost BM. Fleming I. Pergamon; Oxford: 1991. 
• 7 Marek I. Normant JF. In Metal-Catalyzed Cross-Coupling Reactions   Diederich F. Stang PJ. Wiley; Weinheim: 1998.  p.271 
• 8 Frangin Y. Gaudemar M. C. R. Acad. Sci., Ser. C  1975,  280:  1389 
• 9 Bernadou F. Miginiac L. J. Organomet. Chem.  1977,  125:  23 
• 10 Bellassoued M. Frangin Y. Synthesis  1978,  838 
• 11a Carey FA. Sundberg RJ. In Chimie Organique Avancée   3rd ed., Vol. 2:  De Boeck & Larcier; Bruxelles: 1997.  p.247 
• 11b Carey FA. Sundberg RJ. In Chimie Organique Avancée   3rd ed., Vol. 2:  De Boeck & Larcier; Bruxelles: 1997.  p.384 
• 11c Carey FA. Sundberg RJ. In Chimie Organique Avancée   3rd ed., Vol. 2:  De Boeck & Larcier; Bruxelles: 1997.  p.633 
• 12 Viehe HG. Chem. Ber.  1959,  92:  1950 
• 13 Gaudemar M. Bull. Soc. Chim. Fr.  1962,  974