Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Sulfonamides, homoallylic synthesis

Difluoromethyl proline has been prepared by a related approach. Synthesis of cis- and fra 5-4-trifluoromethyl-D-prolines has been performed starting from the Garner aldehyde. 4-Trifluoromethyl, difluoromethylene, or difluoromethyl prolines could also be prepared by 5-endo-trig cyclization of A-(homoallyl)-sulfonamides. ... [Pg.154]

Diastereoselective synthesis of homoallylic amines. The Diels-Alder adducts (2) formed from 1,3-dienes and 1 undergo basic hydrolysis to a single unsaturated sulfonamide (3) via a concerted rctro-cnc reaction. [Pg.455]

This allylation protocol was used in the total synthesis of amphidinolide to give homoallylic alcohol 12 in 72% yield and 17 1 dr (eq 5). Initial transmetallation of stannane 10 with (R,R)-1 via allylic transposition yielded an intermediate borane. Introduction of aldehyde 11 at -78 °C provided for a facile condensation reaction leading to 12. Stereocontrol was induced from the 1,2-diphenylethane sulfonamide auxiliary and could be predicted from a Zimmerman-Traxler model with minimized steric repulsions. The high level of selectivity obtained in this case was a result of a matched diastereomeric transition state featuring the inherent Felkin-Ahn selectivity for nucleophilic attack in aldehyde 11, with the (5)-configuration of the benzoate of 10, as well as the (7 ,7 -antipode of auxiliary 1, resulting in threefold stereodifferentiation. [Pg.93]


See other pages where Sulfonamides, homoallylic synthesis is mentioned: [Pg.6]    [Pg.204]    [Pg.419]   


SEARCH



Homoallyl

Homoallylation

Homoallylic

Sulfonamides, homoallylic

© 2024 chempedia.info