Level 1 – Case 16
Light-Induced Cycloadditions of
N N-Phthaloyl N N N
D D-Amino Acids
Key point: Cycloadditions. SET
N CH
R
COOH
COOMe
N
HO
R
COOMe
hQ
O
O
O
Light-Induced Cycloadditions of N-Phthaloyl D D-Amino
Acids
The irradiation of N
f -phthaloyl
N N
D-amino acids 1 in the presence of electron-deficient olefins, such as methyl acrylate, gives benzopyrrolizidines 2 in good yields
(Scheme 16.1).
N CH
R
COOH
O
O
COOMe
MeCN
R
N
HO
COOMe
O
1
2
hQ
R = H, Me, Ph
Scheme 16.1
Propose a reasonable mechanism to explain how benzopyrrolizidines 2 are
formed.