2-azabicyclo[2.2.2]octa-3,5-dione via a nitrile Diels-Alder reaction.

The hetero-Diels-Alder reaction of an electron-deficient nitrile, p-toluenesulfonyl cyanide, with the silyl enol ether of cyclohexenone produced a hydrolytically sensitive [4 + 2] adduct in good yield. Use of Mander's reagent, ethyl cyanoformate, with the same diene, produced an unstable adduct. Hydrolysis of the tosyl cyanide adduct resulted in the isoquinuclidinone 2-aza[2.

Oxa-di-pi-methane photochemical rearrangement of quinuclidinones. Synthesis of pyrrolizidinones.

[reaction: see text] The oxa-di-pi-methane (ODPM) photochemical rearrangement, a triplet-sensitized sigmatropic 1,2-acyl shift of beta,gamma-enones, was successful utilizing methyl and heptyl 1-aza-3-carboalkoxybicyclo[2.2.2]oct-2-en-5-ones (quinuclidinones) as the photoprecursors.

Synthetic Studies toward the Preparation of Phosphonate Analogs of Sphingomyelin and Ceramide 1-Phosphate Using Pentacovalent Organophospholene Methodology.

Model studies for the syntheses of phosphonate analogs of sphingomyelin and ceramide 1-phosphate are described. The pentacovalent oxaphospholene 3b (derived from methyl vinyl ketone and triethyl phosphite) readily condensed with dialkyl azodicarboxylates (R = Et, t-Bu, CH(2)CCl(3)) to form beta-hydrazido gamma-ketophosphonates 5 and 8 in excellent yields. Cleavage of the N-N bond in 5a (R = Et) or 5b (R = t-Bu) via standard methods was unsuccessful.