Expanding the scope of donor/acceptor carbenes to N-phthalimido donor groups: diastereoselective synthesis of 1-cyclopropane α-amino acids.

Warming of 4-phthalimido-N-mesyl-1,2,3-triazole in the presence of alkenes followed by silica gel induced hydrolysis results in a highly diastereoselective and catalyst-free entry to N-phthalimidocyclopropanecarboxaldehydes.