Use of dilithio-tosylmethyl isocyanide in the synthesis of oxazoles and imidazoles

Product Class 5: Azaindolizines with Two Nitrogen Atoms in the Five-Membered Ring

“…The dilithio derivative of tosylmethyl isocyanide participates as a 1,3dipole in dipolar cyclization with isoquinoline (194) and quinoline (196) and yields the ring-closed products 195 and 197, respectively. [152] Scheme 34 Synthesis of Imidazo[5,1-a]isoquinoline and Imidazo[1,5-a]quinoline [152] TsC(Li) 2 …”

“…H 2 O (10 mL) was added and the soln made alkaline by the addition of 10% NaOH, then extracted with CHCl 3 (3 10 mL). [152] Scheme 43 1,3-Dipolar Cyclization to Imidazo[1,5-a]quinoxaline [152] A special and straightforward ring-closure reaction to imidazo[1,5-a]pyrazines 240±242 starting from 2-(aminoalkyl)pyrazines has been elaborated, [166,173] as shown in Scheme 44. The residue was chromatographed (alumina, 20 g) to give the product as an oil which was crystallized from hexane as a yellow solid; yield: 0.12 g (61%); mp 75±76 8C.…”

An Alkyne‐Metathesis‐Based Approach to the Synthesis of the Anti‐Malarial Macrodiolide Samroiyotmycin A

“…Influenced by prior work, [26] we hypothesised that formation of linchpin fragments 7 (Scheme 1 (ii)) could be achieved through a Schöllkopf‐type condensation of 4‐substituted β‐lactones 8 with anionic TosMIC. [ 27 , 28 , 29 ] If successful, this ambitious strategy would allow simultaneous installation of the 1,3‐oxazole unit and stereochemistry at C(10). Furthermore, we envisaged that construction of the diastereomerically pure β‐lactones 8 would be possible via an asymmetric ketene cycloaddition to α‐methyl aldehydes 9 .…”

An Alkyne‐Metathesis‐Based Approach to the Synthesis of the Anti‐Malarial Macrodiolide Samroiyotmycin A

“…Influenced by prior work, [26] we hypothesised that formation of linchpin fragments 7 (Scheme 1 (ii)) could be achieved through a Schçllkopf-type condensation of 4-substituted b-lactones 8 with anionic TosMIC. [27][28][29] If successful, this ambitious strategy would allow simultaneous installation of the 1,3-oxazole unit and stereochemistry at C (10). Furthermore, we envisaged that construction of the diastereomerically pure b-lactones 8 would be possible via an asymmetric ketene cycloaddition to a-methyl aldehydes 9.…”