Question

N c ?? Gephyrotoxin a) State the molecular formula of gephyrotoxin. b) Give the hybridisation of carbon atoms a and b in gephyrotoxin. c) Determine the number of double-bond equivalents present in gephyrotoxin, explaining your reasoning State the total number of stereoisomers possible for gephyrotoxin, explaining your reasoning. d) e) Assign the absolute stereochemistry (R or S) of the stereogenic centres labelled c and d in the structure of gephyrotoxin above. 14] A simplified fragment of gephyrotoxin is shown below. Draw a plausible chair structure for this fragment, stating which substituents are axial and which are equatorial. f) 9) Rank the following carbocations in order of increasing stability, BRIEFLY explaining your reasoning H2C Ph ??? H C

Answer 1

a) C₁₉H₂₉NO

b)C_a=sp.... C_b=sp³

c)DBE= C+1-H/2+N/2-X(halogen)/2

= 19+1-14.5+0.5

=6

e)C_c= "S"

C_d ="S"