Tetrahedron Letters,Vol.23,No.9,pp 957-960,1982 0040-4039/82/090957-04$03.00/O PrInted In ... RM Moriarty, H. Hu and SC Gupta, Tetrahedrcn Letter, 22, 12f3 (?"-' RM Moriarty, SC Gupta, H ... Sot., 101, 7613 (1979); P. Miiller and J. Godoy, Tetrahedron Letters, 22, 2361 (1981). ...