Synthesis of benzocycloheptene-based amino acid derivatives via a [4+2] cycloaddition reaction as a key step
The seven-membered diene 5 is prepared from 2-butyne-1,4-diol using double orthoester Claisen rearrangement reaction as a key step. The Diels-Alder reaction of the diene 5 with various dienophiles followed by oxidation delivered the benzocycloheptene-based α-amino acid derivatives in very good yields.
Synthesis of constrained α-amino acid derivatives via diels-alder approach
Synthesis of new five and seven membered outer ring diene building blocks containing α-amino acid moiety and their usage in the preparation of the constrained amino acid derivatives is described.