Synthesis of cyclopropanes, cyclobutanes and 6 MR's

what are the 3 methods used to form cyclopropanes

irreversible cyclisation

addition of carbenes to alkenes

addition of carbenoids to alkenes

what are carbenes

extremely reactive, must be generated in situ, can have a singlet or triplet ground state depending on its substituent

what are singlet carbenes

both electrons in one orbital, R = EWG halogen

what are triplet carbenes

one e- in each orbital with same or diff spin, R - EDG alkyl

alpha-elimination

used when cyclopropane synthesised using singlet carbene

how are cyclopropanes synthesised using triplet carbene

via decomposition of diazo compounds

what are carbenoids

metal bound species that exhibit carbene like reactivity, they’re typically more stable and more selective than free carbenes

what are the different methods for synthesising cyclobutanes?

irreversible cyclisation, 2+2 cycloaddition

what are the different methods for synthesising 6 MR’s?

irreversible cyclisation, reversible cyclisation, robinson annulation, diels alder 4+2 cycloaddition, birch reduction

how can you synthesis a 6 membered cyclic acetate

dihydroxy and aldehyde