The reactions of trialkylboranes or B-alkyl-9-BBN with aryl and 1-alkenyl halides take place readily in the presence of PdCl2(dppf) and sodium hydroxide or methoxide to afford alkylated arenes and alkenes in excellent yields.
ABSTRACT The unnatural E isomer of anacardic acid 7 has been synthesized employing the following key steps: Swern oxidation of a diastereoisomeric mixture of β-hydroxyphosphine oxides 13a/b to the corresponding ketone 14 followed by stereospecific reduction to the pure threo isomer 13b which upon treatment with sodium hydride underwent trans elimination to afford the E ester 15.
摘要 漆树酸 7 的非天然 E 异构体的合成采用以下关键步骤:将 β-羟基氧化膦 13a/b 的非对映异构混合物的 Swern 氧化为相应的酮 14,然后立体有择地还原为纯苏式异构体 13b,在处理后与氢化钠进行反式消除,得到 E 酯 15。
Cobalt-catalyzed alkenylation of zinc organometallics
Organozinc halides and diorganozincs undergo cross-coupling reactions with either E- or Z-alkenyl iodides in the presence of catalytic amounts of Co(acac)(2) or Co(acac)(3) in THF:NMP at 55 degrees C leading to polyfunctional alkenes with retention of the stereochemistry of the double bond. (C) 1998 Elsevier Science Ltd. All rights reserved.
A General, Stereoselective Synthesis of<i>trans</i>-Disubstituted Alkenes via Thexylchloroborane
作者:Herbert C. Brown、Hsiupu D. Lee、Surendra U. Kulkarni
DOI:10.1055/s-1982-29744
日期:——
BROWN H. C.; BASAVAIAH D.; KULKARNI SURENDRA U.; LEE HSIUPU D.; NEGISHI E+, J. ORG. CHEM., 51,(1986) N 26, 5270-5276
作者:BROWN H. C.、 BASAVAIAH D.、 KULKARNI SURENDRA U.、 LEE HSIUPU D.、 NEGISHI E+