Asymmetric C-C bond formation using a ruthenium catalyst with chiral counter anion

尝试开发使用具有手性抗衡阴离子部分的钌催化剂的1，7-联烯炔的对映体基团选择性[2+2]环化。虽然各种磷酸根或硫酸根阴离子被用作不对称环化反应的手性阴离子部分，但迄今为止没有得到令人满意的结果。研究了以手性醇为手性阴离子源的反应。实验结果表明，薄荷醇的存在能够以中等的对映选择性得到目标环化产物。另一方面，我们还研究了手性离子液体作为手性阴离子源的可能性。因此，检查了离子液体中的[2+2]环化。结果发现，[BCl 4][PF 6]是用于环化的合适溶剂。此外，含有钌催化剂的离子液体的再循环可达10次。

Attempt to develop enantiotopic group selective [2+2] cyclization of 1,7-allenyne using a ruthenium catalyst having a chiral counter anion part. Although various phosphate- or sulfate-based anions were employed as a chiral anion part for the asymmetric cyclization, no satisfied results were obtained so far. Investigation of the reaction using chiral alcohol as a chiral anion source was also conducted. As a result, it was found that the use of menthol gave gave the desired cyclized product in moderate enantioselectivity.On the other hand, we also investigated the possibility of chiral ionic liquid as a chiral anion source. Thus, the [2+2] cyclization in the ionic liquid was examined. As a result, [BDMI][PF6] was found to be a suitable solvent for the cyclization. Furthermore, recycling the ionic liquid containing the ruthenium catalyst was possible for up to 10 times.