Grandisine D

Part 1 of 1

NaBH₄, H₂SO₄

EtOH, H₂O
-52 °C to RT, 14 h, 84 %

Acrolein, Grubbs-Hoveyda catalyst (2nd gen.)

CH₂Cl₂
RT, 2 h, 84 %

See the Olefin Metathesis

TfOH, Me₂S

MeCN
-35 °C to RT, 2 h, 67 %

Selectivity : 96:04
See the Baylis-Hillman Reaction

(CH₂OH)₂, TsOH

PhH
Reflux, 13 h, 88 %

Also isolated was the C8a-epimer (8 % yield).

NaOEt

EtOH
4 °C to RT, 10 h, 70 %

PhOC(S)Cl, DMAP

CH₂Cl₂
Reflux, 24 h, 100 %

n-Bu₃SnH, AIBN

PhH
Reflux, 30 min, 94 %

See the Barton-McCombie Reaction

TsOH

Acetone, H₂O
Reflux, 15 min, 97 %

n-Bu₂BOTf, i-Pr₂NEt

CH₂Cl₂
-78 °C to RT, 2 h, 100 %

See the Aldol Addition

Dess-Martin Periodinane

CH₂Cl₂
4 °C to RT, 3 h, 88 %

See the Dess-Martin Oxidation

PhSH, HClO₄

MeOH, H₂O
RT, 2 h, 94 %

PhMe, CH₂Cl₂
65 °C, 15 min, 81 %

Me₃O⁺ BF₄^-

MeCN
4 °C to RT, 60 min

NaBH₃CN

MeOH
RT, 60 min, 63 % (2 steps)