Des eseses alcoxytitaniumgenerees par traitement de trichlorotitanio-3propionates d'alkyles (I) avec un demi-equivalent d'alcoolate de titane (IV) sont plus reactors que I, Fournissant des voies d'acces a des hydroxy-4esters, γ-内酯和环丙烷羧酸盐。同烯醇化物形成机制的讨论
A stereochemical study on the intramolecular hydrosilylation of α,β-unsaturated esters
摘要:
The intramokcular hydrosilylation of several 3-methyl-4-siloxy-2-butenoates afforded cis disubstituted lactones after desilylation. The diastereoinduction was sensitive to the bulk of the allylic substituent, but not to the groups on silicon. The origin of asymmetric induction is believed to be the A1,2 strain from the beta-methyl group.
Silyl Phosphites. XVIII. Versatile Utility of α-(Trimethylsilyloxy)alkylphosphonates as Key Intermediates for Transformation of Aldehydes into Several Carbonyl Derivatives
作者:Mitsuo Sekine、Masashi Nakajima、Akiko Kume、Akio Hashizume、Tsujiaki Hata
DOI:10.1246/bcsj.55.224
日期:1982.1
trimethylsilyl phosphite (DTMSP) with aldehydes were converted, by treatment with lithium diisopropylamide (LDA) followed by the successive alkylation and alkalinehydrolysis, to carbonyl derivatives involving aldehydes, unsymmetrical ketones, β,γ-unsaturated ketones, and carboxylic acids. β-Substituted carboxylic esters and γ-substituted lactones were prepared by use of the carbonyl addition compounds of DTMSP
A new radical cyclization method for the formation of C(sp3)–C(sp3) and C–O bonds via MnO2-promoted alkene carboesterification with anhydrides is developed.
Ni(acac)(2) catalyzes homoallylation of aldehydes with 1,3-dienes in the presence of triethylborane. Triethylborane serves as a reducing agent delivering a formal hydride to the C2 position of 1,3-dienes, thus generating a formal homoallyl anion species and enabling the novelhomoallylation of aldehydes. The reaction proceeds smoothly at room temperature in the absence of any phosphane or nitrogen
Samariumdi-iodide is an efficient reagent for the reductivecoupling of ketones or aldehydes and electron-deficientalkenes, whereby γ-lactones can be prepared in good yields from ethyl acrylate.
Chemo- and Stereoselective Crotylation of Aldehydes and Cyclic Aldimines with Allylic <i>gem</i>-Diboronate Ester
作者:Jinyoung Park、Seoyoung Choi、Yeosan Lee、Seung Hwan Cho
DOI:10.1021/acs.orglett.7b01821
日期:2017.8.4
We report a highlychemo- and stereoselective crotylation of aldehydes and cyclic aldimines with allylic-gem-diboronate ester as a new type of organoboron reagent. The allylic-gem-diboronate ester undergoes the crotylation with aldehydes and cyclic aldimines in excellent stereoselectivity, forming anti-5,6-disubstituted oxaborinin-2-ols or (E)-δ-boryl-anti-homoallylic amines in high efficiency. The