A New Approach to Macrocyclization via Alkene Formation in Catalytic Diazo Decomposition. Synthesis of Patulolides A and B

[reaction: see text] Effective synthetic uses of bisdiazocarbonyl compounds for the selective construction of diverse macrocycles, including the synthesis of patulolides A and B, by catalytic "carbene dimer" formation are reported. Control of stereochemistry and efficient methods for product isomerization or kinetic isomer differentiation have been achieved.