Big Chemical Encyclopedia

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

Articles Figures Tables About

Organostannanes Lewis acid promotion

Lewis acids catalyse the addition of allylic organostannanes or organosilanes to aldehydes. In contrast to the thermal reactions of allylboranes or allylstannanes, the use of a Lewis acid promotes reaction via an acyclic transition state. With a y-substituted allylsilane, such as crotyltrimethylsilane 156, the E-isomer reacts with excellent selectivity for the syn product (1.149). The corresponding Z-isomer (of 156) also favours the syn product, although with reduced selectivity (64 36). The transition state is thought to involve the ahgnment of the two tt-bonds 180° to one another (1.150). [Pg.72]

MECHANISTIC VARIABILITY IN THE LEWIS ACID-PROMOTED REACTIONS OF ALDEHYDES WITH ORGANOSTANNANES... [Pg.73]

Other reactions of organostannanes. Hydrostannylation of allenes catalyzed by Pd(0) is regiochemically distinct from reactions promoted by Lewis acids [e.g.,... [Pg.365]


See other pages where Organostannanes Lewis acid promotion is mentioned: [Pg.327]    [Pg.340]    [Pg.327]    [Pg.340]    [Pg.327]    [Pg.340]    [Pg.498]    [Pg.345]    [Pg.345]    [Pg.515]    [Pg.345]   
See also in sourсe #XX -- [ Pg.327 ]

See also in sourсe #XX -- [ Pg.327 ]

See also in sourсe #XX -- [ Pg.327 ]

See also in sourсe #XX -- [ Pg.327 ]




SEARCH



Acidity promotion

Lewis acids 2 + 2-, promotion

Lewis acids promoters

Lewis promoter

Organostannanes

Promoters acidic

© 2024 chempedia.info