Abstract
N-Cbz-(alpha-aminoacyl)benzotriazoles 5a-e reacted with (stabilized-methylene)triphenylphosphoranes 6 and 13 to give the corresponding esters 7a-e (66-91%) or nitriles 14a-e (63-85%). Deprotection of N-Cbz-gamma-amino-beta-oxo-alpha-triphenylphosphoranylidene esters 7a-d induced cyclization to form 2,4-dioxo-3-triphenylphosphoranylidene pyrrolidines 9a-c (20-98%) and 1,3-dioxo-2-triphenylphosphoranylidene tetrahydropyrrolizine 9d (79%). N-Cbz-delta-amino-beta-oxo-alpha-triphenylphosphoranylidene ester 7e cyclized to form 2,4-dioxo-3-triphenylphosphoranylidene piperidine 9e (60%). Deprotection of N-Cbz-gamma-amino-beta-oxo-alpha-triphenylphosphoranylidene nitriles 14a-d similarly formed 5-amino-4-triphenylphosphonio-2,4-dihydropyrrol-3-one bromides 15a-c (70-72%) and 3-ammonio-2-triphenylphosphoniotetrahydropyrrolizin-1-one dibromide 15d (66%). N-Methyl pyrrolidine 11 was transformed into 3,3-dibromopyrrolidin-2,4-dione 16 (79%), 3,3-dibromo-5-hydroxypyrrolidin-2,4-dione 17 (88%), 4-azido-3-bromopyrrol-2-one 18 (84%), and 4-benzotriazol-1-ylpyrol-2-one 19 (92%).