Synthesis and Absolute Configuration at C(8) of ‘ p ‐Menthane‐3,8,9‐triol’ Derived from (–)‐Isopulegol

Two diastereoisomers of the new, potentially insecticidal ‘ p ‐menthane‐3,8,9‐triol’ (=(2 S )‐ and (2 R )‐ 2‐[(1 R ,2 R ,4 R )‐2‐hydroxy‐4‐methylcyclohexyl]propane‐1,2‐diol; (8 S )‐ and (8 R )‐ 1 ), have been synthesized from (–)‐isopulegol by both conventional dihydroxylation and catalytic Sharpless dihydroxylation ( Scheme ). The absolute configuration at C(8) of the corresponding orthoformate adduct (8 S )‐ 3a was determined by 1 H‐NMR and X‐ray crystallographic analysis ( Figure ).