Cationic Three-component Coupling Involving an Optically Active Enamine Derivative. From Time Integration to Space Integration of Reactions

Abstract

Three-component coupling of an N-acyliminium cation pool, an optically active 2-t-butyloxazole derivative, and a carbon nucleophile such as allyltrimethylsilane was effectively achieved by a rapid one-pot method at −78 °C and a flow microreactor method at 0 °C.

Exploiting Ruthenium Carbene-Catalyzed Reactions in Total Synthesis of Marine Oxacyclic Natural Products

“…7 These non-metathetic reactions can be integrated 45 with metathetic reactions in a single reaction vessel; tandem metathetic/non-metathetic processes using a Grubbstype ruthenium complex are useful for rapid generation of molecular complexity from simple materials. 7a,7b However, the application of tandem metathetic/non-metathetic reactions to total synthesis of complex natural products is still in its infancy.…”

“…After ozonolysis of the styryl group of trans-50, the derived aldehyde was reacted with CrCl 2 /CHI 3 53 to give the iodoolefin trans-51, which was coupled with an alkylborane, prepared by hydroboration of the olefin 52 with 9-BBN-H, under the influence of aqueous Cs 2 CO 3 and PdCl 2 (dppf )/Ph 3 As to afford the olefin trans-53. Hydrolysis of the methyl ester and benzoate moieties, Yamaguchi macrolactonization of the resultant seco-acid, and removal of the MOM group furnished the correct structure of aspergillide B (45). Total synthesis of the correct structure of aspergillide A (44) was achieved in the same manner.…”

Thioamides and Thioformamides for Sequential Reactions with Organolithium and Grignard Reagents

“…The importance of one-pot sequential reactions has been well-documented, 22 and these have been categorized as time integration. 23 The protocol in eq 5 is the first example of time integration using thioiminium salts to our best knowledge, and is widely applicable, 24 due to the ready availability of a range of thioiminium salts. Therefore, we applied one-pot sequential reactions to thioiminium salts 6 derived from aliphatic and aromatic thioamides 5 for the synthesis of N,N-dialkyl-2-propynylamines with a tertiary carbon atom adjacent to a nitrogen atom.…”

A flow-microreactor approach to protecting-group-free synthesis using organolithium compounds

“…Flowmicroreactor synthesis has also received much attention from the viewpoint of synthesis based on reaction integration [26][27][28][29][30] and green sustainable synthesis 31 . Such successful applications speak well for the power of the flow-microreactor method in chemical synthesis.…”