A one-flask synthesis of dihydronaphthalenemethanols by directed addition of organolithium reagents to BHA naphthalenecarboxylates

The 1,4-addition reaction of organolithium reagents with 2,6-bis(tert-butyl )-4-methoxyphenyl naphthalenecarboxylates gave regioselectively substituted dihydronaphthalenecarboxylates in high yields. Successive treatment of the esters with organolithiums in THF, lithium triethylborohydride, methyl iod ide, and finally sodium borohydride in methanol, provided regio- and stereo selectively the corresponding 1,1,2 and 1,2,2-trisubstituted dihydronaphtha lenylmethanols in good yields. This one-flask process is constituted from a sequence of five reactions involving a reductive generation of an aldehyde metal enolate from a ketene as the key step. (C) 1999 Elsevier Science Ltd . All rights reserved.