A cobalt-complexed propyanl in organic synthesis: A highly stereoselective total synthesis of bengamide E
作者:Chisato Mukai、Osamu Kataoka、Miyoji Hanaoka
DOI:10.1016/0040-4039(94)85036-4
日期:1994.9
A highlystereoselective aldol reaction of the cobalt-complexed 4-methylpent-2-ynal 2 with O-silyl ketene O,S-acetal 3 provided the syn-aldol product, which was subsequently converted to (+)-bengamide E through optical resolution and the second diastereoselective aldol reaction as crucial steps.
Highly enantio- and diastereoselective boron aldol reactions of α-heterosubstituted thioacetates with aldehydes and silyl imines
作者:Cesare Gennari、Anna Vulpetti、Gilles Pain
DOI:10.1016/s0040-4020(97)00251-2
日期:1997.4
Boron enolates derived from α-heterosubstituted thioacetates and bearing menthone-derived chiral ligands react with aldehydes to give anti aldols with excellent diastero- and enantiocontrol. Boron enolates derived from tert-butyl α-halothioacetate and bearing menthone-derived chiral ligands react with imines with excellent diastero- and enantiocontrol to give syn α-halo-β-aminothioesters, which can
Pt-Catalyzed Rearrangement of Oxaspirohexanes to 3-Methylenetetrahydrofurans: Scope and Mechanism
作者:Christian A. Malapit、Sampada M. Chitale、Meena S. Thakur、Rosa Taboada、Amy R. Howell
DOI:10.1021/acs.joc.5b00604
日期:2015.5.15
A novel Pt-catalyzed rearrangement of oxaspirohexanes to 3-methylenetetrahydrofurans is reported. Mechanistic studies by 13C-labeling experiments confirm oxidative addition of Pt(II) regioselectively to the least substituted carbon–carbon bond of the cyclopropane to form a platinacyclobutane intermediate. To our knowledge, this is the first alkoxy-substituted platinacyclobutane that has been observed
Access to Oxetane-Containing <i>psico</i>-Nucleosides from 2-Methyleneoxetanes: A Role for Neighboring Group Participation?
作者:Yanke Liang、Nathan Hnatiuk、John M. Rowley、Bryan T. Whiting、Geoffrey W. Coates、Paul R. Rablen、Martha Morton、Amy R. Howell
DOI:10.1021/jo201565h
日期:2011.12.16
of the powerful antiviral natural product, oxetanocin A, has been readily synthesized from cis-2-butene-1,4-diol. Key 2-methyleneoxetane precursors were derived from β-lactones prepared by the carbonylation of epoxides. F+-mediated nucleobase incorporation provided the corresponding nucleosides in good yield but with low diastereoselectivity. Surprisingly, attempted exploitation of anchimeric assistance
An efficient method for the optical resolution of 3-hydroxy-2-substituted-4-alkynoates: a highly stereoselective total synthesis of (+)-bengamide E1
作者:Chisato Mukai、Osamu Kataoka、Miyoji Hanaoka
DOI:10.1021/jo00123a030
日期:1995.9
A novel. procedure for the optical resolution of 3-hydroxy-2-substituted-4-alkynoates and its application to the stereoselective total synthesis of (+)-bengamide E are described. 3-Hydroxy-2-substituted-4-alkynoates, derived from the aldol reaction of cobalt-complexed propynals with ketene O-silyl O,S-acetals, were easily resolved by the formation of a chiral carbamate followed by cobalt complexation. Chiral 2-(benzyloxy)-3-hydroxy-4-alkynoate derivatives thus obtained were used as starting materials for a highly stereoselective total synthesis of (+)-bengamide E.