Kinetic Resolution of α‐Silyl‐Substituted Allylboronate Esters via Chemo‐ and Stereoselective Allylboration of Aldehydes
作者:Jinyoung Park、Yongsuk Jung、Jeongho Kim、Eunsung Lee、Sarah Yunmi Lee、Seung Hwan Cho
DOI:10.1002/adsc.202001170
日期:2021.4.27
We describe the kinetic resolution of α‐silyl‐substituted allylboronate esters via chiral phosphoric acid‐catalyzed chemo‐, diastereo‐ and enantioselective allylboration of aldehydes. This process provides two synthetically versatile enantioenriched compounds, (Z)‐δ‐silyl‐substituted anti‐homoallylic alcohols and α‐silyl‐substituted allylboronate esters, with a selectivity factor up to 328. We propose
Selective C−C Coupling of Vinyl Epoxides with Diborylmethide Lithium Salts
作者:Riccardo Gava、Elena Fernández
DOI:10.1002/chem.201901406
日期:2019.6.18
Vinyl epoxides and styrene oxide can react with diborylmethide lithiumsalts through an exclusive SN2 borylmethylation/ring opening in a regio‐ and diastereoselective way, depending on the nature of the substrate. The ring‐opening protocol provides homoallylboronates that can be transformed into challenging diastereomeric bishomoallylic alicyclic 1,3‐diols. Unprecedented 3‐borylated 1,2‐oxaborolan‐2‐ol
取决于底物的性质,乙烯基环氧化物和苯乙烯氧化物可以通过排他性和非对映选择性的方式,通过专有的S N 2硼甲基化/开环与甲基二硼化锂盐反应。开环方案提供了高烯丙基硼酸酯,可以将其转化为具有挑战性的非对映体双烯丙基烯丙基脂环式1,3-二醇。通过硼甲基化/ 2-甲基-2-乙烯基环氧乙烷的开环,然后进行分子内环化,制备了史无前例的3-硼化的1,2-氧杂硼烷-2-醇产品。
Transborylation of alkenylboranes with diboranes
作者:Paula Dominguez-Molano、Gerard Bru、Oriol Salvado、Ricardo J. Maza、Jorge J. Carbó、Elena Fernández
DOI:10.1039/d1cc05815k
日期:——
Exchange of boryl moieties between alkenylboranes and diboron reagents has been postulated as a stereospecific cross-metathesis pathway with concomitant formation of mixed diboron reagents. DFT calculations propose a mechanism for the stereocontrolled C(sp2)–B/B′–B′ cross-metathesis with both symmetric and non-symmetric diboron reagents.
Diborylalkyllithium Salts Trigger Regioselective Ring Opening of Vinyl Aziridines
作者:Oriol Salvado、Riccardo Gava、Elena Fernández
DOI:10.1021/acs.orglett.9b03672
日期:2019.11.15
nucleophilic attack on vinyl aziridines with controlled regioselectivity. Preferred SN2 diborylalkylation ringopening reaction on the less sterically hindered position is observed with 1-tosyl-2-vinylaziridine, whereas exclusive SN2′ nucleophilic attack occurs on 2-methyl-1-tosyl-2-vinylaziridine. Cyclic vinyl aziridines interact through a third venue, via SN2 diborylalkylation ringopening reaction on the allylic
经LiTMP处理的gem -Diborylalkanes生成α-diborylalkane锂碱,该碱对区域的乙烯基氮丙啶进行亲核攻击,并具有可控的区域选择性。优选的小号Ñ就少的空间位阻的位置2 diborylalkylation开环反应与1-甲苯磺酰基-2- vinylaziridine观察到的,而排斥小号Ñ上2-甲基-1-对甲苯磺酰-2- vinylaziridine发生2'的亲核攻击。环状乙烯基氮丙啶经由烯丙基位置上的S N 2二硼烷基烷基化开环反应通过第三位点相互作用。在完全立体化学控制下形成均烯丙基二硼酸酯。
Synthesis of Allylboronates via Zweifel‐type Deprotonative Olefination
作者:Nuo Xu、Jianeng Xu、Qing Zhu、Chao Liu
DOI:10.1002/adsc.202001351
日期:2021.4.27
allylboronates via Zweifel‐type deprotonative olefination was demonstrated. Tetrasubstituted vinylboronates were used as the substrates. NCS (N‐chlorosuccinimide) was used as a bifunctional additive, electrophile and base. This method exhibited a different elimination strategy in Zweifel type transformation to afford allylboronates. The homo‐alcohols and alkenes were stereoselective synthesized from the obtained