supported by their 1H, 13C NMR spectra and microanalyses or HRMS results. The

methylene groups between the two nitrogens in 2.11a-f appeared at around 4.0 ppm as

singlets.

 The benzotriazolyl group in 2.9a-c can be substituted by cyano anion to give 2-(3-

substituted-1-imidazolidinyl)acetonitriles 2.12a-c in 77-97% yields. Reaction of 2.9a

with benzenethiol in the presence of sodium hydride produced 1-phenyl-3-(phenyl-

thiomethyl)imidazolidine (2.13) in 66% yield. The benzotriazolyl group in 2.9a was

replaced in the presence of ZnBr2 by a P-nucleophile (triethyl phosphite) to afford diethyl

(3-phenyl-l-imidazolidinyl)methylphosphonate (2.14) in 70% yield. The Lewis acid

ZnBr2 facilitates loss of the benzotriazolyl anion to form an iminium cation, which is then

attacked by the P-nucleophile. [00JOC3683] Thus, various useful functionalities were

introduced to the imidazolidine ring system via nucleophilic substitution of the

benzotriazolyl group.

2.2.3 Syntheses of Optically Active Imidazolidines. (cf. Scheme 2-3)

 We further investigated the preparation of optically active imidazolidines starting

from commercially available N-Boc-a-amino acids 2.15a-c. Based on our recent

paper,[01JCS(P1)1767] a-amino amides 2.17a-c were easily obtained in two steps from

the optically active N-Boc-a-amino acids 2.15a-c (R3 = Me, i-Bu, or PhCH2) and 4-

methylphenylamine. Crombie and Hooper reduced 2-amino-N-phenylpropanamide with

LiA1H4 to 2-aminopropylaniline without reporting a detailed procedure.[55JCS3010] We

found that refluxing of 2.17b (R3 = i-Bu) with 3 equiv of LiAlH4 in dry THF for 1 day

gave a 1:1 mixture of 2.17b and 2.18b. When 6 equiv of LiAlH4 in dry THF for 2 days

was used, reduction of 2.17a-c afforded chiral diamines 2.18a-c in more than 90%