No abstract

The generation of, and subsequent reactions with, 1-silyl-substituted organolithiums with CO was carried out using serially connected flow microreactors. The flow system proved to be quite useful for the carbonylation of silyl-substituted organolithiums under slightly pressurized conditions of CO, which was created conveniently by the use of a back-pressure regulator. This flow system, coupled with heating, accelerated the carbonylation reaction of 1-silyl-substituted organolithiums and allowed the stable silyl-substituted alkyllithium, 1,3-disilylallyllithium, which was not effective in a batch-flask reaction under a CO atmosphere, to participate in an efficient carbonylation reaction.

Significance:The authors report the generation and subsequent reaction of 1-silyl-substituted organolithiums with CO using serially connected flow microreactors. Compared to batch conditions, the flow system coupled with heating to 80°C and using pressurized CO via back pressure regulator accelerated the reaction clearly (4-10 min instead of 1-10 h). Comment: Substrates like 1,3-disilylallyllithiums, that did not react in a carbonylation reaction with electrophilic trapping, were reacted successfully under the flow conditions. BPR TMEDA, THF n-BuLi hexane CO EX OE SiR 1 3 R 2 4-6 atm t 1 25 °C t 2 80 °C 1 min 25 °C (6 equiv) SiR 1 3 = SiMe 3 , SiPhMe 2 R 1 = vinyl, Ph, TMS ethenyl EX = Me 3 SiCl, MeI, 4-ClC 6 H 4 CHO Selected examples: O SiR 1 3 R 2 E or SiMe 3 O Ph 77% yield t 1 = 31 min t 2 = 4 min 77-93% yield SiPhMe 2 OSiMe 3 93% yield (E/Z = 93:7) t 1 = 18 min t 2 = 10 min SiMe 3 OSiMe 3 88% yield (1E,3E/1Z,3E/1E,3Z = 87:9:4) t 1 = 18 min t 2 = 10 min Me 3 Si Ph SiMe 3 OSiMe 3 88% yield (E/Z = 97:3) t 1 = 31 min t G e o r g T h i e m e V e r l a g S t u t t g a r t · N e w Y o r k Categor y Metal-Mediated Synthesis Key words flow lithium carbonylation Downloaded by: University of Illinois at Chicago. Copyrighted material.