Topics in Current Chemistry (2018) 376:46
1 3
first a noncatalytic formation of the required anhydride using a tubular reactor, followed by the catalytic step into the packed-bad reactor leading to the final product
24 with high enantioselectivity. An in-line IR analysis at the outlet of the packedbed reactor allowed controlling the conversion, while introduction of water facilitated the removal of pivalic acid and i-Pr 2 NEt by the in-line liquid–liquid separator.
Enantioenriched adduct 24 (er > 99:1) was obtained by simple evaporation of the
continuously collected organic phases with 70% yields and in more than 4 g after
11 h operation.
Supported catalyst deserving to be mentioned for the green compliance, are supported ionic liquids. An example of the use of the so-called supported ionic liquidlike phases (SILLPs) under continuous flow conditions has been reported by Luis
et al. [48]. Supported catalyst SILLP-25 was used for the development of continuous
flow synthesis of cyanohydrin trimethylsilyl ethers 26 (Scheme 13). The effect of the
morphology of the polymer (gel-type or macroporous bead resins or, alternatively,
a monolithic polymer) was studied, and a gel-type support was selected for the
implementation of the flow synthesis. Flow conditions were optimized using in-line
Scheme 11 Use of modified squaramide supported catalyst for a two-step continuous flow process
40
Reprinted from the journal
1 3
first a noncatalytic formation of the required anhydride using a tubular reactor, followed by the catalytic step into the packed-bad reactor leading to the final product
24 with high enantioselectivity. An in-line IR analysis at the outlet of the packedbed reactor allowed controlling the conversion, while introduction of water facilitated the removal of pivalic acid and i-Pr 2 NEt by the in-line liquid–liquid separator.
Enantioenriched adduct 24 (er > 99:1) was obtained by simple evaporation of the
continuously collected organic phases with 70% yields and in more than 4 g after
11 h operation.
Supported catalyst deserving to be mentioned for the green compliance, are supported ionic liquids. An example of the use of the so-called supported ionic liquidlike phases (SILLPs) under continuous flow conditions has been reported by Luis
et al. [48]. Supported catalyst SILLP-25 was used for the development of continuous
flow synthesis of cyanohydrin trimethylsilyl ethers 26 (Scheme 13). The effect of the
morphology of the polymer (gel-type or macroporous bead resins or, alternatively,
a monolithic polymer) was studied, and a gel-type support was selected for the
implementation of the flow synthesis. Flow conditions were optimized using in-line
Scheme 11 Use of modified squaramide supported catalyst for a two-step continuous flow process
40
Reprinted from the journal