Ito A, Kishida M, Kurusu Y, Masuyama Y
Department of Chemistry, Faculty of Science and Technology, Sophia University, 7-1 Kioicho, Chiyoda-ku, Tokyo 102-8554, Japan.
J Org Chem. 2000 Jan 28;65(2):494-8. doi: 10.1021/jo991403o.
Regio- and diastereoselective carbonyl allylations of 1-halobut-2-enes with tin(II) halides are described. Tin(II) bromide in a dichloromethane-water biphasic system is an effective reagent for unusual alpha-regioselective carbonyl allylation of 1-bromobut-2-ene to produce 1-substituted pent-3-en-1-ols. The addition of tetrabutylammonium bromide (TBABr) to the biphasic system produces 1-substituted 2-methylbut-3-en-1-ols via usual gamma-addition which is opposite to the alpha-addition without TBABr. The gamma-addition to aromatic aldehydes exhibits anti-diastereoselectivity, while that to aliphatic aldehydes is not diastereoselective. The allylation of benzaldehyde by 1-chlorobut-2-ene in 1,3-dimethylimidazolidin-2-one (DMI) does not occur with tin(II) chloride or bromide but does proceed with tin(II) iodide and exhibits gamma-syn selectivity which is unusual for a Barbier-type carbonyl allylation. In the carbonyl allylation by 1-chlorobut-2-ene with any tin(II) halide, the addition of tetrabutylammonium iodide (TBAI) accelerates the reaction and enhances gamma-syn selectivity. The use of tin(II) iodide and TBAI produces 2-methyl-1-phenylbut-3-en-1-ol with high yield and high syn-diastereoselectivity. The syn-diastereoselective carbonyl allylation of 1-chlorobut-2-ene using tin(II) iodide, a catalytic amount of TBAI, and NaI in DMI-H(2)O is applied to various aldehydes.
本文描述了1-卤代丁-2-烯与卤化锡（II）的区域和非对映选择性羰基烯丙基化反应。二氯甲烷-水双相体系中的溴化锡（II）是一种有效的试剂，可用于1-溴丁-2-烯的异常α-区域选择性羰基烯丙基化反应，生成1-取代的戊-3-烯-1-醇。向双相体系中加入四丁基溴化铵（TBABr），通过与无TBABr时相反的通常γ-加成反应生成1-取代的2-甲基丁-3-烯-1-醇。对芳香醛的γ-加成反应表现出反非对映选择性，而对脂肪醛的γ-加成反应则没有非对映选择性。在1,3-二甲基咪唑啉-2-酮（DMI）中，1-氯丁-2-烯与氯化锡（II）或溴化锡（II）不发生苯甲醛的烯丙基化反应，但与碘化锡（II）反应并表现出γ-顺式选择性，这对于巴比耶型羰基烯丙基化反应来说是不寻常的。在1-氯丁-2-烯与任何卤化锡（II）的羰基烯丙基化反应中，加入四丁基碘化铵（TBAI）可加速反应并提高γ-顺式选择性。使用碘化锡（II）和TBAI可高产率和高顺式非对映选择性地生成2-甲基-1-苯基丁-3-烯-1-醇。在DMI-H₂O中，使用碘化锡（II）、催化量的TBAI和NaI对1-氯丁-2-烯进行顺式非对映选择性羰基烯丙基化反应可应用于各种醛。
