68070-07-5Relevant articles and documents
STEREOHOMOGENEUS SYNTHESIS OF (E)- AND (Z)-CROTYLTRIFLUOROSILANES AND HIGHLY STEREOSELECTIVE ALLYLATION OF ALDEHYDES
Kira, Mitsuo,Hino, Takakazu,Sakurai, Hideki
, p. 1099 - 1102 (1989)
Stereohomogeneus (E)- and (Z)-crotyltrifluorosilanes were prepared and used for the highly diastereoselective synthesis of threo- and erythro-β-methylhomoallyl alcohols, respectively, from aldehydes in the presence of fluoride ions.The mechanism of the reaction was discussed.
Titanocene(III)-promoted Barbier-type crotylation of carbonyl compounds
Sancho-Sanz, Iris,Miguel, Delia,Millan, Alba,Estevez, Rosa E.,Oller-Lopez, Juan L.,Alvarez-Manzaneda, Enrique,Robles, Rafael,Cuerva, Juan M.,Justicia, Jose
experimental part, p. 732 - 735 (2011/03/20)
A mild, highly regio-and stereoselective method for the crotylation of aldehydes and ketones mediated/catalyzed by titanocene(III) is described. Optimized conditions permit the selective generation of γ-adducts in high yields together with high stereoselectivity, with a predominance of anti stereoisomers.
Addition of crotyltitanocenes to aldehydes: Influence of cyclopentadienyl substituents on the diastereoselective formation of homoallylic alcohols
Collins, Scott,Dean, Warren P.,Ward, David G.
, p. 2289 - 2293 (2008/10/08)
The addition of (η3-crotyl)titanocenes (2, R = H, Me, i-Pr) to primary, secondary, and tertiary aldehydes has been investigated. The products of this reaction, homoallylic alcohols, are formed with good to excellent selectivity favoring the anti diastereomer in all cases. The degree of diastereoselectivity correlates with the size of the substituent on the cyclopentadienyl ring and that on the aldehyde. For aliphatic and aromatic aldehydes an increase in diastereoselectivity with increasing steric hindrance at the metal center was observed. The results are consistent with a chairlike transition state for product formation involving slippage of the η3-allyl ligand of the allyltitanocene to η1 with retention of allyl geometry.
ALLYLIC ORGANOMETALLIC WAY TO CONTROL ACYCLIC STEREOCHEMISTRY AND ITS APPLICATION TO THE SYNTHESIS OF CARBOHYDRATES
Yamamoto, Yoshinori,Komatsu, Toshiaki,Maruyama, Kazuhiro
, p. 31 - 42 (2007/10/02)
The Cram/anti-Cram selectivity in the reactions of allylmetals with aldehydes and the erythro/threo selectivity in the reactions of substituted allylic organometallic compounds with other aldehydes can be controlled by the metal (M).Based on both selectiv
STEREO- AND REGIOCONTROL OF ACYCLIC SYSTEMS VIA THE LEWIS ACID MEDIATED REACTION OF ALLYLIC STANNANES WITH ALDEHYDES
Yamamoto, Yoshinori,Yatagai, Hidetaka,Ishihara, Yuji,Maeda, Norihiko,Maruyama, Kazuhiro
, p. 2239 - 2246 (2007/10/02)
The reaction of crotyltrialkylstannanes (1) with aldehydes in the presence of BF3*OEt2 produces the corresponding erythro homoallyl alcohols (2) predominantly regardless of the geometry of the double bond. Further, the Lewis acid mediated reaction exhibits the enhanced Cram selectivity in comparison with other allylic organometallic reactions which proceed in the absence of Lewis acids.Use of AlCl3-i-PrOH as the Lewis acid entirely changes the reaction course; the linear adduct (12) is produced rather than the branched adduct (13).The reaction of 1-BF3*OEt2 system is applied to the short and stereoselective synthesis of the (+/-) Prelog-Djerassi lactonic acid (16) and (-) verrucarinolactone (19).
CROTYLZIRCONIUM DERIVATIVES AS A NEW REAGENT FOR THE THREO SELECTIVE SYNTHESIS OF β-METHYLHOMOALLYL ALCOHOLS
Yamamoto, Yoshinori,Maruyama, Kazuhiro
, p. 2895 - 2898 (2007/10/02)
Crotylzirconium derivatives, prepared from the reaction of crotylmagnesium chloride or crotyllithium with bis(cyclopentadienyl)zirconium dichloride, undergo a rapid reaction with aldehydes to afford the threo product predominantly.The ratio of Cram/anti-Cram product via this reagent is ca. 75/25 ca. 60/40.
