由手性仲烷基碘化物通过保留性I / Li交换,然后用CuBr⋅P(OEt)3进行保留性重金属化,制备了手性仲烷基铜试剂。将溶剂转换为THF可显着提高其构型稳定性,并使这些铜试剂适合于区域选择性的烯丙基取代。光学富集的铜物质经过烯丙基溴的S N 2取代(最高> 99%S N 2区域选择性)。ZnCl 2的添加和手性烯丙基磷酸酯的使用允许将区域选择性转向S N 2'取代(高达> 99%S N 2'区域选择性)并执行高度选择性的抗-S N 2'替换,具有对两个相邻立体中心的绝对控制。该方法用于三种蚂蚁信息素(+)-紫杉醇,(+)-13-正法烷醛和(+)-法烷醛的合成(最高98:2 dr,99%ee)。
(+)-Faranal , the trailpheromone of Pharaoh'sant, was synthesized in 10 % overall yield starting from an easily available chiral building block and employing diastereoselective carbon—carbon bond formation.
Methyl 3-bromomethyl-3-butenoate as an isopentane building block for the stereoselective preparation of (S)-4-methyl-3,6-dihydro-2H-pyran-2-carbaldehyde and (+)-faranal
作者:Iryna V. Mineyeva、Oleg G. Kulinkovich
DOI:10.1016/j.tetlet.2010.01.120
日期:2010.4
(S)-4-Methyl-3,6-dihydro-2H-pyran-2-carbaldehyde (3), the common intermediate in the syntheses of the C17-C27 subunit of laulimalide (4) and (+)-faranal (5), the trail pheromone of the pharaoh ant, Monomorium pharaonis, were obtained via transformation of methyl 3-bromomethyl-3-butenoate (1) into allylstannane 2 and subsequent allylation of (benzyloxy)acetaldehyde (6) in accordance with the Keck procedure as the key steps. (C) 2010 Elsevier Ltd. All rights reserved.
(+)-Faranal 1a, the trailpheromone of Pharaoh'sant, and its congener, (+)-13-norfaranal 1b were synthetized from chiral building block 4 employing diastereoselective carbon-carbon bond formation. The application of crude pig liver esterase enzyme for the preparation of 4 is also discussed.
Regio- and Stereoselective Allylic Substitutions of Chiral Secondary Alkylcopper Reagents: Total Synthesis of (+)-Lasiol, (+)-13-Norfaranal, and (+)-Faranal
作者:Juri Skotnitzki、Lukas Spessert、Paul Knochel
DOI:10.1002/anie.201811330
日期:2019.1.28
reagents were preparedfrom chiral secondary alkyl iodides by a retentive I/Li exchange followed by a retentive transmetalation with CuBr⋅P(OEt)3. Switching the solvent to THF significantly increased their configurational stability and made these copper reagents suitable for regioselective allylic substitutions. The optically enriched copper species underwent SN2 substitutions with allylic bromides (up to
由手性仲烷基碘化物通过保留性I / Li交换,然后用CuBr⋅P(OEt)3进行保留性重金属化,制备了手性仲烷基铜试剂。将溶剂转换为THF可显着提高其构型稳定性,并使这些铜试剂适合于区域选择性的烯丙基取代。光学富集的铜物质经过烯丙基溴的S N 2取代(最高> 99%S N 2区域选择性)。ZnCl 2的添加和手性烯丙基磷酸酯的使用允许将区域选择性转向S N 2'取代(高达> 99%S N 2'区域选择性)并执行高度选择性的抗-S N 2'替换,具有对两个相邻立体中心的绝对控制。该方法用于三种蚂蚁信息素(+)-紫杉醇,(+)-13-正法烷醛和(+)-法烷醛的合成(最高98:2 dr,99%ee)。