Studies on the syntheses of heterocyclic compounds. 675. A facile regiospecific and stereocontrolled synthesis of a diterpene alkaloid intermediate from benzocyclobutenes

Total Synthesis of A‐Nor B‐Aromatic OSW‐1 Aglycon: A Highly Effective Approach to Optically Active trans‐4,5‐Benzhydrindane

“…To prepare the allyl alcohol 8 , benzocyclobutene derivative 9 10 was converted into alcohol 10 in three steps in a 67% overall yield, according to the reported procedure 11. Swern oxidation of 10 and Horner−Wadsworth−Emmons reaction of the resulting aldehyde proceeded smoothly to afford the conjugated ester 11 , which was subjected to DIBAL reduction to provide the desired allyl alcohol 8 in high yields.…”

Synthetic strategies toward hetidine and hetisine-type diterpenoid alkaloids

“…2) was identified by Pelletier 10 as a versatile intermediate that was used in various early synthetic studies toward diterpenoid alkaloids in the atisane or kaurane class. [11][12][13][14][15] While this seminal work was not directed specifically at the hetidine or hetisine frameworks, much of the work that followed from other investigators adopted similar intermediates (e.g., 8) as targets (vide infra).…”

Alkaloids

“…Repeated Polonovski reaction followed by introduction of a hydroxyl group completed the synthesis of vinblastine. Vincristine (374) was synthesized from vinblastine (373) by selective oxidation of the N-methyl function of vindoline with the Jones reagent at low temperature. Villalstonine (376) is obtained from several Alstonia species.…”

“…Veatchine (397) and garryine (399) have a kaurene skeleton, and they are the positional isomers of an aminoethanol unit. Synthesis of these last three alkaloids was accomplished by Nagata [373], whereas the efficient synthesis of the key intermediate for these alkaloids was achieved by Kametani [374]. Delphinine (400), chasmanine (401), and aconitine (402) are grouped into the aconitine type, which has no oxygen functional group or substituent at the C-7 position, whereas the lycoctonine type bears oxygen functional groups at the C-6 and C-7 positions.…”