SYNTHESIS OF HETEROCYCLES
257
IV.F-20 Denmark, S.E. and Schnute, M.E., JOC, 59, 4576.
OG*
1. Pt 2 0, H 2
160 psi
X ^ '''OCOR
2 TsCl, DBU
OCH 3 3. NaOH
OCH,
H 3 CO
H3CO
75%
96% ee
IV.F-21 Arnold, D.P. et al., AJC, 47, 969 and 975; Montforts, F.P. et al.,
TL, 35, 9703; Tang, J. and Verkade, J.G., JOC, 59, 7793; Lash, T.D. et
al., TL, 35, 2493.
S0 2 C 6 H 4 Me
CNCH 2 C0 2 Et
THF
base
22-67% H
IV.F-22 Clark, J.S. and Hodgson, P.B., CC, 2701.
Cu(acac) 2
Ph-H
2 reflux
,o
[2,3]
39-84%