DPPA-Promoted decarbonylation of a N-Cbz-(D,L)-Pipecolinic acid derivative: An easy entry to [4.5]spirolactams and [4.5]spirolactones. Total synthesis of (±)-δ-coniceine
摘要:
The synthesis of 6-benzyloxycarbonyl-1-oxa-6-azaspiro[4.5]decane-2-one 7a and 6-benzyloxycarbonyl-1,6-diazaspiro[4.5]decane-2-one 7b from (D,L)-pipecolinic acid is described. The extremely clean decarbonylation of the alpha-substituted amino acid 9d promoted by diphenylphosphorazidate (DPPA) is the key step of our strategy. The total synthesis of (+/-)-delta-coniceine (16) from the enamine ester 10a has been successfully achieved.
DPPA-Promoted decarbonylation of a N-Cbz-(D,L)-Pipecolinic acid derivative: An easy entry to [4.5]spirolactams and [4.5]spirolactones. Total synthesis of (±)-δ-coniceine
摘要:
The synthesis of 6-benzyloxycarbonyl-1-oxa-6-azaspiro[4.5]decane-2-one 7a and 6-benzyloxycarbonyl-1,6-diazaspiro[4.5]decane-2-one 7b from (D,L)-pipecolinic acid is described. The extremely clean decarbonylation of the alpha-substituted amino acid 9d promoted by diphenylphosphorazidate (DPPA) is the key step of our strategy. The total synthesis of (+/-)-delta-coniceine (16) from the enamine ester 10a has been successfully achieved.