DIASTEREOSELECTIVE HYDROFORMYLATION OF CHIRAL ALKENES IN ORGANIC SYNTHESIS

有机合成中手性烯烃的非对映选择性加氢甲酰化

基本信息

批准号：
12650859
负责人：
YAMAMOTO Keiji
金额：
$ 1.98万
依托单位：
TOKYO UNIVERSITY OF SCIENCE, YAMAGUCHI
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

Taking advantage of hydroformylation of alkenes in organic synthesis, the rhodium complex-catalyzed hydroformylation of chiral allylic alcohols was examined. Despite of related hydrogenation with excellent diastereoselectivity in the product based on a potential hydroxyl group-directed assistance, hydroformylation exhibited an inverse selectivity in the major diastereoisomer. Accordingly, hydroformylation of a non-functionalized substrate, 4-t-butylmethylenecyclohexane (1), using [Rh(acac)(CO)_2] as a catalyst precursor was examined in detail in terms of diastereoselectivity in the products, trans- (2) and cis-4-t-butyl-cyclohexylacetaldehyde (3), as a function of applied initial pressure of syn-gas (H_2-CO = 1 : 1). It was clearly demonstrated that the conversion to aldehydes was found to be satisfactory under a higher pressure of syn-gas (5 - 9.5 MPa), the distereoselectivity 2 : 3 being deteriorated uniformly as the initial pressure increased, while under a lower pressure of syn-gas (2 - 0.5 MPa), diastereoselecivity 2 : 3 became satisfactorily high (up to 92 : 8) at the expense of the formation of a regioisomeric aldehyde, cis-4-t-butyl-1-methylcyclohexane-carboxaldehyde (4) as well as much isomerization of 1 into 4-t-butyl-1-methylcyclohexene (5) These results may well be interpreted in terms of a kinetic controlled insertion of the substrate 1 into [HRh(CO)_n], under a higher pressure of syn-gas, resulting in lower diastereoselectivity of 2 : 3, whereas a thermodynamic controlled step of substrate insertion into [HRh(CO)_n] under a lower pressure may give rise to the observed isomerization to 4 or inverse insertion to form 5, at the same time, affording the highest diastereoselectivity 2 : 3 = 92.8.Use of [Rh(acac)(CO)_2]-[Ru_3(CO)_<12>] as a co-catalyst was found to depress any isomerization of 1, keeping the diastereoselectivity 2 : 3 intact. Thus, the co-catalyst system has averted cleanly a dilemma observed above.

利用烷烃在有机合成中的氢甲基化中，检查了手性烯丙基醇的铑复合物催化的氢甲酰化。尽管基于潜在的羟基指导的辅助，在产品中具有极好的非对映选择性的相关氢化，但在主要的非对映异构体中，氢甲基化表现出反相反的选择性。因此，使用[RH（ACAC）（CO）_2]作为催化剂前体的非功能化底物4-T-丁基甲基甲基环己烷（1）的加氢甲基化在产物中详细研究了催化剂前体，以详细研究，trans-（trans-（2）和cis-4-t-4-t-4-tbutylycylycylacy forligy of-4-tblohexyl a andycylycy frounction（3） Syn-Gas的初始压力（H_2-CO = 1：1）。 It was clearly demonstrated that the conversion to aldehydes was found to be satisfactory under a higher pressure of syn-gas (5 - 9.5 MPa), the distereoselectivity 2 : 3 being deteriorated uniformly as the initial pressure increased, while under a lower pressure of syn-gas (2 - 0.5 MPa), diastereoselecivity 2 : 3 became satisfactorily high (up to 92 : 8) at the expense of the formation在区域性异构醛中，顺式-4-T-叔丁基1-甲基环己烷 - 羧甲醛（4）以及1分成4-T-丁基-1-甲基环己烯中的异构化（5）这些结果很可能会在较高的插入基础上解释为较高的插入率（kinter）的插入率（kin）。 syn-gas, resulting in lower diastereoselectivity of 2 : 3, whereas a thermodynamic controlled step of substrate insertion into [HRh(CO)_n] under a lower pressure may give rise to the observed isomerization to 4 or inverse insertion to form 5, at the same time, affording the highest diastereoselectivity 2 : 3 = 92.8.Use of [RH（ACAC）（CO）_2] - [RU_3（CO）_ <12>]作为共催化剂，可以降低1个异构化1，保持映射性2：3完整。因此，共催化剂系统的避免了上面观察到的困境。