Macrocystidia cucumis

One of the best methods to synthesize cyclopentenone derivatives is the Pauson-Khand procedure. However, Shindo s group have recently developed a domino process consisting of a [2+2] cycloaddition of a ketone with anynolate, followed by a Dieckmann condensation to give a 3-lactone as 4-190 which is decarboxylated under reflux in toluene in the presence of silica gel to afford cyclopentenones [64a]. Thus, the reaction of 4-188 and 4-189 led to 4-190, which on heating furnished the linear cucumin 4-191 (Scheme 4.41). This natural product has been isolated from the mycelial cultures of the agaric Macrocystidia cucumis [65, 66]. The domino procedure described was also used to synthesize dihydrojasmone and a-cuparenone. Moreover, the [2+2] cycloaddition can be combined with a Michael reaction [64b]. 

Other cyclisations seem to proceed via humulene. From the basidiomycete Macrocystidia cucumis the linear T. arthrosporone (hirsutane type) and novel cu-cumane derivatives, the cucumins A-H have been isolated, e.g. cucumins A and B. 

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

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