Synthesis 2006(21): 3711-3714  
DOI: 10.1055/s-2006-950293
PAPER
© Georg Thieme Verlag Stuttgart · New York

Copper(I) Chloride Mediated Cyclization of Optically Active 2,3-Allenoic Acids or 1:1 Salts of Optically Active 2,3-Allenoic Acids with Chiral Amines

Shengming Ma*, Zhanqian Yu
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, P. R. of China
e-Mail: masm@mail.sioc.ac.cn;
Further Information

Publication History

Received 1 May 2006
Publication Date:
09 October 2006 (online)

Abstract

Copper(I) chloride mediated cyclization of optically active 2,3-allenoic acids or 1:1 salts of optically active 2,3-allenoic acids with chiral amines was developed. The reaction of optically active 2,3-allenoic acids in methanol requires only a catalytic amount of copper(I) chloride, while the reaction of the 1:1 salts of optically active 2,3-allenoic acids with chiral amines needs one equivalent of copper(I) chloride and should be carried out in dichloromethane to ensure high efficiency of chirality transfer.

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Crystal data for compound (R)-(+)-2e: C13H13BrO2, M = 281.14, monoclinic, space group P2 (1), Mo Kα, final R indices [I > 2σ(I)], R1 = 0.0657, wR2 = 0.1570, a = 4.3321 (19) Å, b = 10.916 (5) Å, c = 13.117 (6) Å, α = 90°, β = 92.942 (7)°, γ = 90°, V = 619.5 (5) Å3, T = 293 (2) K, Z = 2, reflections collected/unique: 3518:2213 (R int = 0.1593), no observation [I > 2σ(I)] 957, parameters 155; CCDC 602980 contains the data.