Stereocontrolled approach to the highly functionalized bicyclo[3.2.0] heptane core of bielschowskysin through intramolecular Cu(I)-catalyzed [2+2] photocycloaddition

Thermal and Photochemical Mechanisms for Cyclobutane Formation in Bielschowskysin Biosynthesis

“…Various synthetic approaches towards the construction of the central cyclobutane ring in 2 have now been described using a [2+2] photocycloaddition. [2][3][4][5][6] Biosynthetic speculations have been made to account for the formation of bielschowskysin from rubrifolide (1) in which enzymatic oxidation steps are followed by an intramolecular [2+2] ring closure (Scheme 1). 7 Photochemical reactions play a large role in natural product synthesis, 8 and many cyclobutanes are thought to arise from photochemical reactions.…”

“…Various synthetic approaches towards the construction of the central cyclobutane ring in 2 have now been described using a [2+2] photocycloaddition. [2][3][4][5][6] Biosynthetic speculations have been made to account for the formation of bielschowskysin from rubrifolide…”

Photochemical [2+2] cycloaddition reaction of enone derivatives with 2-silyloxy-1H-pyrrole derivatives

“…The strained cyclobutane [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] and oxetane [21][22][23] structures are important in organic synthesis. After Ciamician discovered the first example of photochemical [2+2] cycloaddition reaction, 24 Paternò, following Ciamician, reported the first photochemical [2+2] oxetane formation reaction using light irradiation.…”

An Approach Toward the Bridged 14‐Membered Carbon Macrocycle of Bielschowskysin

“…Hexacyclic natural product 1 is arguably one of the most complex furanocembranoids known to date, as it features an unprecedented cis ‐fused tricyclo[9.3.0.0 2,10 ]tetradecane ring system and 11 stereogenic centers . Numerous groups including our own have communicated efforts towards the total synthesis of bielschowskysin . Although the synthesis of the natural product has not been accomplished yet, our contribution relying on non‐photochemical and photochemical strategies resulted in several advanced intermediates containing the crucial stereogenic center, the cyclobutane moiety, and fully substituted southern as well as northern hemispheres of the target molecule , .…”